Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Nov. 02, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	BRO
Entity Registrant Name	BROWN & BROWN, INC.
Entity Central Index Key	0000079282
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		279,210,227

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
REVENUES
Commissions and fees	$ 529,813	$ 474,609	$ 1,502,219	$ 1,383,899
Investment income	719	491	2,051	1,085
Other income, net	318	546	1,228	22,047
Total revenues	530,850	475,646	1,505,498	1,407,031
EXPENSES
Employee compensation and benefits	268,045	246,062	790,902	736,445
Other operating expenses	83,697	72,058	243,704	210,289
(Gain)/loss on disposal	1,106	(1,902)	(1,544)	(1,993)
Amortization	21,637	21,435	62,961	64,402
Depreciation	5,259	5,489	16,410	17,242
Interest	8,963	9,393	28,686	28,949
Change in estimated acquisition earn-out payables	(357)	(1,308)	2,528	8,309
Total expenses	388,350	351,227	1,143,647	1,063,643
Income before income taxes	142,500	124,419	361,851	343,388
Income taxes	36,447	48,506	91,048	131,263
Net income	$ 106,053	$ 75,913	$ 270,803	$ 212,125
Net income per share:
Basic (in dollars per share)	$ 0.38	$ 0.27	$ 0.98	$ 0.76
Diluted (in dollars per share)	0.38	0.27	0.96	0.74
Dividends declared per share (in dollars per share)	$ 0.075	$ 0.068	$ 0.225	$ 0.203

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 422,971	$ 573,383
Restricted cash and investments	301,716	250,705
Short-term investments	12,843	24,965
Premiums, commissions and fees receivable	736,378	546,402
Reinsurance recoverable	98,516	477,820
Prepaid reinsurance premiums	344,955	321,017
Other current assets	95,799	47,864
Total current assets	2,013,178	2,242,156
Fixed assets, net	89,772	77,086
Goodwill	2,929,634	2,716,079
Amortizable intangible assets, net	680,226	641,005
Investments	17,152	13,949
Other assets	72,844	57,275
Total assets	5,802,806	5,747,550
Current Liabilities:
Premiums payable to insurance companies	732,550	685,163
Losses and loss adjustment reserve	98,475	476,721
Unearned premiums	344,955	321,017
Premium deposits and credits due customers	107,788	91,648
Accounts payable	84,228	64,177
Accrued expenses and other liabilities	234,731	228,748
Current portion of long-term debt	30,000	120,000
Total current liabilities	1,632,727	1,987,474
Long-term debt less unamortized discount and debt issuance costs	832,361	856,141
Deferred income taxes, net	284,330	256,185
Other liabilities	113,980	65,051
Shareholders’ Equity:
Common stock, par value $0.10 per share; authorized 560,000 shares; issued 286,961 shares and outstanding 276,074 shares at 2018, issued 286,929 shares and outstanding 276,210 shares at 2017 - in thousands. 2017 share amounts restated for the 2-for-1 stock split effective March 28, 2018	29,011	28,692
Additional paid-in capital	525,465	483,730
Treasury stock, at cost at 10,887 shares at 2018 and 10,719 shares at 2017, respectively - in thousands.	(397,572)	(386,322)
Retained earnings	2,782,504	2,456,599
Total shareholders’ equity	2,939,408	2,582,699
Total liabilities and shareholders’ equity	$ 5,802,806	$ 5,747,550

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	560,000,000	560,000,000
Common stock, shares issued (in shares)	290,108,823	286,929,229
Common stock, shares outstanding (in shares)	279,222,277	276,210,910
Treasury stock shares (in shares)	10,886,546	10,718,319

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Line Items]
Document Period End Date			Sep. 30, 2018
Payments of Debt Issuance Costs			$ 0	$ (2,809)
Cash, Cash Equivalents and Restricted Cash			724,687	823,207	$ 824,088	$ 781,283
Cash flows from operating activities:
Net income	$ 106,053	$ 75,913	270,803	212,125
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	21,637	21,435	62,961	64,402
Depreciation	5,259	5,489	16,410	17,242
Non-cash stock-based compensation			23,522	22,362
Change in estimated acquisition earn-out payables	(357)	(1,308)	2,528	8,309
Deferred income taxes			(16,416)	23,941
Amortization of debt discount			118	119
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Amortization Expense			1,102	1,309
Accretion (Amortization) of Discounts and Premiums, Investments			(4)	20
Payments On Acquisition Earn Outs In Excess Of Original Estimated Payables			(11,775)	(13,800)
Net gain on sales of investments, fixed assets and customer accounts			(1,259)	(1,739)
Changes in operating assets and liabilities, net of effect from acquisitions and divestitures:
Premiums, commissions and fees receivable decrease			(24,560)	(23,350)
Reinsurance recoverables decrease			379,304	(2,082,203)
Prepaid reinsurance premiums decrease			(23,938)	(23,585)
Other assets decrease			(9,052)	(5,314)
Premiums payable to insurance companies (decrease)			19,179	5,585
Premium deposits and credits due customers increase			16,089	14,030
Losses and loss adjustment reserve (decrease)			(378,246)	2,082,203
Unearned premiums (decrease)			23,938	23,585
Accounts payable increase			27,817	22,113
Accrued expenses and other liabilities (decrease)			(21,465)	1,018
Other liabilities (decrease)			(1,539)	(34,802)
Net cash provided by operating activities			355,517	313,570
Cash flows from investing activities:
Additions to fixed assets	(9,469)	(4,049)	(28,859)	(12,897)
Payments for businesses acquired, net of cash acquired			(254,836)	(26,478)
Proceeds from sales of fixed assets and customer accounts			3,338	4,085
Purchases of investments			(8,897)	(10,393)
Proceeds from Sale, Maturity and Collection of Investments			17,551	5,178
Net cash used in investing activities			(271,703)	(40,505)
Cash flows from financing activities:
Payments on acquisition earn-outs			(13,337)	(25,488)
Payments on long-term debt			(115,000)	(91,750)
Issuances of common stock for employee stock benefit plans			19,406	17,387
Repurchase Of Stock Benefit Plan Shares For Employees To Fund Tax Withholdings			(11,928)	(6,791)
Purchase of treasury stock			(11,250)	(57,389)
Settlement (prepayment) of accelerated share repurchase program			11,250	(7,500)
Cash dividends paid			(62,356)	(56,801)
Net cash used in financing activities			(183,215)	(231,141)
Net increase in cash and cash equivalents inclusive of restricted cash			(99,401)	41,924
Cash and cash equivalents inclusive of restricted cash at end of period	$ 422,971	$ 546,520	$ 422,971	$ 546,520	$ 573,383	$ 515,646

Nature of Operations	9 Months Ended
Nature of Operations	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of OperationsBrown & Brown, Inc., a Florida corporation, and its subsidiaries (collectively, “Brown & Brown” or the “Company”) is a diversified insurance agency, wholesale brokerage, insurance programs and services organization that markets and sells to its customers, insurance products and services, primarily in the property, casualty and employee benefits areas. Brown & Brown’s business is divided into four reportable segments: the Retail Segment provides a broad range of insurance products and services to commercial, public and quasi-public entities, professional and individual customers; the National Programs Segment, acting as a managing general agent (“MGA”), provides professional liability and related package products for certain professionals, a range of insurance products for individuals, flood coverage, and targeted products and services designated for specific industries, trade groups, governmental entities and market niches, all of which are delivered through nationwide networks of independent agents, including Brown & Brown retail agents; the Wholesale Brokerage Segment markets and sells excess and surplus commercial insurance, primarily through independent agents and brokers, including Brown & Brown Retail offices; and the Services Segment provides insurance-related services, including third-party claims administration and comprehensive medical utilization management services in both the workers’ compensation and all-lines liability arenas, as well as Medicare Set-aside services, Social Security disability and Medicare benefits advocacy services, and claims adjusting services.

Basis of Financial Reporting

9 Months Ended

Sep. 30, 2018

Condensed Financial Information of Parent Company Only Disclosure [Abstract]

Basis of Financial Reporting

The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of recurring accruals) necessary for a fair presentation have been included. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the Notes thereto set forth in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017.

The preparation of these financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, as well as disclosures of contingent assets and liabilities, at the date of the Condensed Consolidated Financial Statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates.

Recently Issued Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” (“ASU 2016-02”), which provides guidance for accounting for leases. Under ASU 2016-02, the Company will be required to recognize the assets and liabilities for the rights and obligations created by leased assets with initial maturities greater than one year. In July 2018, the FASB also issued ASU 2018-10 and ASU 2018-11 related to Topic 842. ASU 2018-10 narrows certain aspects of the guidance issued in the amendments within ASU 2016-02. ASU 2018-11 provides entities with an additional transition method to adopt ASU 2016-02. Under this new transition method, an entity initially applies ASU 2016-02 at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ASU 2016-02, along with ASU 2018-10 and ASU 2018-11, will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company continues to evaluate the impact of this pronouncement with the principal impact expected to be that the present value of the remaining lease payments will be presented as a liability on the balance sheet as well as an asset of similar value representing the “Right of Use” for those leased properties. The Company plans to adopt Topic 842 under the transition method provided by ASU 2018-11. The undiscounted contractual cash payments remaining on leased properties were $210.4 million as of December 31, 2017 as indicated in Note 13 of the Company's Form 10-K and $209.8 million as of September 30, 2018 as detailed in the Liquidity and Capital Resources section of this Quarterly Report on Form 10-Q.

In August 2018, the FASB issued ASU 2018-15, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract,” which provides guidance for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The Company is currently evaluating the impact of this pronouncement.

Recently Adopted Accounting Standards

In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force)" (“ASU 2016-15”), which addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified and applies to all entities, required to present a statement of cash flows under Topic 230. ASU 2016-15 became effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017 with early adoption permitted. The Company adopted

ASU 2016-15 effective January 1, 2018 and has determined there is no impact on the Company’s Statement of Cash Flows. The Company already presented cash paid on contingent consideration in business combination as prescribed by ASU 2016-15 and does not, at this time, engage in the other activities being addressed in this ASU.

In March 2016, the FASB issued ASU 2016-08, “Principal Versus Agent Considerations (Reporting Revenue Gross Versus Net)” (“ASU 2016-08”) to clarify certain aspects of the principal-versus-agent guidance included in the new revenue standard ASU 2014-09 “Revenue from Contracts with Customers” (“ASU 2014-09”). The FASB issued the ASU in response to concerns identified by stakeholders, including those related to (1) determining the appropriate unit of account under the revenue standard’s principal-versus-agent guidance and (2) applying the indicators of whether an entity is a principal or an agent in accordance with the revenue standard’s control principle. The Company adopted ASU 2016-08 effective contemporaneously with ASU 2014-09 beginning January 1, 2018. The impact of ASU 2016-08 was limited to the claims administering activities of one of our businesses within our Services Segment and therefore was not material to the net income of the Company.

In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“Topic 606”), which provides guidance for revenue recognition. Topic 606 affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non-financial assets. It supersedes the revenue recognition requirements in Topic 605, “Revenue Recognition,” and most industry-specific guidance. The standard’s core principle is that a company should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which a company expects to be entitled in exchange for those goods or services. Effective as of January 1, 2018, the Company adopted ASU 2014–09, and all related amendments, which established Accounting Standards Codification ("ASC") Topic 606. The Company adopted these standards by recognizing the cumulative effect as an adjustment to opening retained earnings at January 1, 2018, under the modified retrospective method for contracts not completed as of the day of adoption. The cumulative impact of adopting Topic 606 on January 1, 2018 was an increase in retained earnings within stockholders’ equity of $117.5 million. Under the modified retrospective method, the Company is not required to restate comparative financial information prior to the adoption of these standards and, therefore, such information presented for the three and nine months ended September 30, 2017 continues to be reported under the Company's previous accounting policies.

The following areas are impacted by the adoption of Topic 606:

Historically, approximately 70% of the Company’s commissions and fees are in the form of commissions paid by insurance carriers. These commissions are earned at a point in time upon the effective date of bound insurance coverage, as no significant performance obligation remains after coverage is bound. If there are other services within the contract, the Company estimates the stand-alone selling price for each separate performance obligation, and the corresponding apportioned revenue is recognized over a period of time as the performance obligations are fulfilled. In situations where multiple performance obligations exist within a contract, the use of estimates is required to allocate the transaction price on a relative stand-alone selling price basis to each separate performance obligation.

Commission revenues - Prior to the adoption of Topic 606, commission revenues, including those billed on an installment basis, were recognized on the latter of the policy effective date or the date that the premium was billed to the client, with the exception of the Company's Arrowhead businesses, which followed a policy of recognizing these revenues on the latter of the policy effective date or processed date in our systems. As a result of the adoption of Topic 606, certain revenues associated with the issuance of policies are now recognized upon the effective date of the associated policy. These commission revenues, including those billed on an installment basis, are now recognized earlier than they had been previously. Revenue is now accrued based upon the completion of the performance obligation, thereby creating a current asset for the unbilled revenue, until such time as an invoice is generated, which typically does not exceed twelve months. The Company does not expect the overall impact of these changes to be significant on a full-year basis, but the timing of recognizing revenue will impact our fiscal quarters when compared to prior years. For the nine months ended September 30, 2018, the adoption of Topic 606 increased base and incentive commissions revenue, as defined in Note 3, by $26.6 million compared to what would have been recognized under the Company's previous accounting policies. Incentive commissions include additional commissions over base commissions received from insurance carriers based on predetermined production levels mutually agreed upon by both parties.

Profit-sharing contingent commissions - Prior to the adoption of Topic 606, revenue that was not fixed and determinable because a contingency existed was not recognized until the contingency was resolved. Under Topic 606, the Company must estimate the amount of consideration that will be received in the coming year such that a significant reversal of revenue is not probable. Profit-sharing contingent commissions represent a form of variable consideration associated with the placement of coverage, for which we earn commissions and fees. In connection with Topic 606, profit-sharing contingent commissions are estimated with a constraint applied and accrued relative to the recognition of the corresponding core commissions. The resulting effect on the timing of recognizing profit-sharing contingent commissions will now more closely follow a similar pattern as our commissions and fees with any true-ups recognized when payments are received or as additional information that affects the estimate becomes available. For the nine months ended September 30, 2018, the adoption of Topic 606 reduced profit-sharing contingent commissions revenue by $6.9 million compared to what would have been recognized under our previous accounting policies.

Fee revenues - Approximately 30% of the Company’s commissions and fees are in the form of fees, which are predominantly in the Company's National Programs and Services Segments, and to a lesser extent in the large accounts business within the Company's Retail Segment, where the Company receives fees in lieu of a commission. In accordance with Topic 606, fee revenue from certain agreements are recognized in earlier periods and others in later periods as compared to our previous accounting treatment depending on when the services within the contract are satisfied and when we have transferred control of the related services to the customer. The Company does not expect the overall impact of these changes to be significant on a full-year basis, but the timing of recognizing fees revenue will impact our fiscal quarters when compared to prior years. For the nine months ended September 30, 2018, the adoption of Topic 606 increased fees revenue by $5.0 million compared to what would have been recognized under our previous accounting policies.

Additionally, the Company has evaluated ASC Topic 340 - Other Assets and Deferred Cost (“ASC 340”) which requires companies to defer certain incremental cost to obtain customer contracts, and certain costs to fulfill customer contracts.

Incremental cost to obtain - The adoption of ASC 340 resulted in the Company deferring certain costs to obtain customer contracts primarily as they relate to commission-based compensation plans in the Retail Segment, in which the Company pays an incremental amount of compensation on new business. These incremental costs are deferred and amortized over a 15-year period, which is consistent with the analysis performed on acquired customer accounts and referenced in Note 7 to the Company’s condensed consolidated financial statements. For the nine months ended September 30, 2018, the Company deferred $10.3 million of incremental cost to obtain customer contracts. The Company expensed $0.3 million of the incremental cost to obtain customer contracts for the nine months ended September 30, 2018.

Cost to fulfill - The adoption of ASC 340 resulted in the Company deferring certain costs to fulfill contracts and to recognize these costs as the associated performance obligations are fulfilled. In order for contract fulfillment costs to be deferred under ASC 340, the costs must (1) relate directly to a specific contract or anticipated contract, (2) generate or enhance resources that the Company will use in satisfying its obligations under the contract, and (3) be expected to be recovered through sufficient net cash flows from the contract. The Company does not expect the overall impact of these changes to be significant on a full-year basis, but the timing of recognizing these expenses will impact quarterly results compared to prior years as such recognition better aligns with the associated revenue. With the modified retrospective adoption of Topic 606, the Company deferred $52.7 million in contract fulfillment costs on its opening balance sheet on January 1, 2018 based upon the estimated average time spent on policy renewals. For the nine months ended September 30, 2018, the Company had net expense of $3.6 million related to the release of previously deferred contract fulfillment costs associated with performance obligations that were satisfied in the period, net of current year deferrals for costs incurred that related to performance obligations yet to be fulfilled.

In connection with the implementation of this standard, we modified, and in some instances instituted, additional accounting procedures, processes and internal controls. While the relative impacts of this standard to our revenue streams is significant, we do not view these modifications and additions as a material change in our internal controls over financial reporting.

The cumulative effect of the changes made to our unaudited condensed consolidated balance sheet as of January 1, 2018 for the adoption of Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” and Accounting Standards Codification Topic 340 – Other Assets and Deferred Cost (the “New Revenue Standard”):



(in thousands)	Balance at December 31, 2017		Adjustments due to the New Revenue Standard		Balance at January 1, 2018
Balance Sheet
Assets:
Premiums, commissions and fees receivable	$	546,402	$	153,058	$	699,460
Other current assets	47,864		52,680		100,544

Liabilities:
Premiums payable to insurance companies	685,163		12,107		697,270
Accounts payable	64,177		8,747		72,924
Accrued expenses and other liabilities	228,748		22,794		251,542
Deferred income taxes, net	256,185		44,575		300,760

Shareholders' Equity:
Retained earnings	2,456,599		117,515		2,574,114

The $52.7 million adjustment to other current assets reflects the deferral of certain cost to fulfill contracts. The $12.1 million adjustment to premiums payable to insurance companies reflects the estimated amount payable to outside brokers on unbilled premiums, commissions and fees receivable.

The following table illustrates the impact of adopting the New Revenue Standard has had on our reported results in the unaudited condensed consolidated statement of income.



	Nine months ended September 30, 2018
(in thousands)	As reported		Impact of adopting the New Revenue Standard			Balances without the New Revenue Standard
Statement of Income
Revenues:
Commissions and fees	$	1,502,219	$	24,700		$	1,477,519

Expenses:
Employee compensation and benefits	790,902		(3,396		)	794,298
Other operating expenses	243,704		6,996			236,708
Income taxes	91,048		5,309			85,739

Net income	$	270,803	$	15,791		$	255,012

- Definition

The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.

+ References + Details

Revenues (Notes)

9 Months Ended

Sep. 30, 2018

Disaggregation of Revenue [Line Items]

Disaggregation of Revenue [Table Text Block]

The following tables present the revenues disaggregated by revenue source:



	Three months ended September 30, 2018
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Base commissions⁽¹⁾	$	207,703	$	92,106	$	62,216	$	—	$	(11	)	$	362,014
Fees⁽²⁾	33,915		43,168		13,887		48,054		(360		)	138,664
Incentive commissions⁽³⁾	11,408		287		44		—		16			11,755
Profit-sharing contingent commissions⁽⁴⁾	5,280		7,786		1,261		—		—			14,327
Guaranteed supplemental commissions⁽⁵⁾	2,573		22		458		—		—			3,053
Investment income⁽⁶⁾	1		138		44		51		485			719
Other income, net⁽⁷⁾	207		12		99		—		—			318
Total Revenues	$	261,087	$	143,519	$	78,009	$	48,105	$	130		$	530,850



	Nine months ended September 30, 2018
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Base commissions⁽¹⁾	$	609,252	$	249,491	$	174,888	$	—	$	(42	)	$	1,033,589
Fees⁽²⁾	94,282		106,839		37,799		137,878		(880		)	375,918
Incentive commissions⁽³⁾	43,356		295		515		—		28			44,194
Profit-sharing contingent commissions⁽⁴⁾	17,879		17,290		4,824		—		—			39,993
Guaranteed supplemental commissions⁽⁵⁾	7,277		75		1,173		—		—			8,525
Investment income⁽⁶⁾	2		384		125		160		1,380			2,051
Other income, net⁽⁷⁾	758		60		401		—		9			1,228
Total Revenues	$	772,806	$	374,434	$	219,725	$	138,038	$	495		$	1,505,498


(1)	Base commissions generally represent a percentage of the premium paid by an insured and are affected by fluctuations in both premium rate levels charged by insurance companies and the insureds’ underlying “insurable exposure units,” which are units that insurance

companies use to measure or express insurance exposed to risk (such as property values, or sales and payroll levels) to determine what premium to charge the insured. Insurance companies establish these premium rates based upon many factors, including loss experience, risk profile and reinsurance rates paid by such insurance companies, none of which we control.


(2)	Fee revenues relate to fees for services other than securing coverage for our customers and fees negotiated in lieu of commissions.


(3)	Incentive commissions include additional commissions over base commissions received from insurance carriers based on predetermined production levels mutually agreed upon by both parties.


(4)	Profit-sharing contingent commissions are based primarily on underwriting results, but may also reflect considerations for volume, growth and/or retention.


(5)	Guaranteed supplemental commissions represent guaranteed fixed-base agreements in lieu of profit-sharing contingent commissions.


(6)	Investment income consists primarily of interest on cash and investments.


(7)	Other income consists primarily of legal settlements and other miscellaneous income.

Contract Assets and Liabilities

The balances of contract assets and contract liabilities arising from contracts with customers as of September 30, 2018 and December 31, 2017 were as follows:



(in thousands)	September 30, 2018		December 31, 2017⁽¹⁾
Contract assets	$	249,294	$	210,323
Contract liabilities	$	63,611	$	51,236


(1)	The balances as of December 31, 2017 have been revised to reflect the impact of adopting the New Revenue Standard.

Unbilled receivables (contract assets) arise when the Company recognizes revenue for amounts which have not yet been billed in our systems. Deferred revenue (contract liabilities) relates to payments received in advance of performance under the contract before the transfer of a good or service to the customer.

As of September 30, 2018, deferred revenue consisted of $53.9 million as current portion to be recognized within one year and $9.7 million in long term to be recognized beyond one year. As of December 31, 2017, deferred revenue consisted of $44.5 million as current portion to be recognized within one year and $6.7 million in long-term deferred revenue to be recognized beyond one year.

During the nine months ended September 30, 2018, the amount of revenue recognized related to performance obligations satisfied in a previous period, inclusive of changes due to estimates, was approximately $8.1 million.

Net Income Per Share

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Net Income Per Share

Net Income Per ShareBasic net income per share is computed based on the weighted average number of common shares (including participating securities) issued and outstanding during the period. Diluted net income per share is computed based on the weighted average number of common shares issued and outstanding plus equivalent shares, assuming the exercise of stock options. The dilutive effect of stock options is computed by application of the treasury-stock method. The following is a reconciliation between basic and diluted weighted average shares outstanding:



	For the three months ended September 30,						For the nine months ended September 30,
(in thousands, except per share data)	2018			2017			2018			2017
Net income	$	106,053		$	75,913		$	270,803		$	212,125
Net income attributable to unvested awarded performance stock	(2,716		)	(1,852		)	(6,185		)	(5,181		)
Net income attributable to common shares	$	103,337		$	74,061		$	264,618		$	206,944
Weighted average number of common shares outstanding – basic	278,132			279,512			276,744			280,024
Less unvested awarded performance stock included in weighted average number of common shares outstanding – basic	(7,124		)	(6,820		)	(6,321		)	(6,840		)
Weighted average number of common shares outstanding for basic net income per common share	271,008			272,692			270,423			273,184
Dilutive effect of stock options	4,274			5,094			5,191			4,838
Weighted average number of shares outstanding – diluted	275,282			277,786			275,614			278,022
Net income per share:
Basic	$	0.38		$	0.27		$	0.98		$	0.76
Diluted	$	0.38		$	0.27		$	0.96		$	0.74

Business Combinations

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Business Combinations

During the nine months ended September 30, 2018, Brown & Brown acquired the assets and assumed certain liabilities of fifteen insurance intermediaries, all of the stock of three insurance intermediaries and one book of business (customer accounts). Additionally, miscellaneous adjustments were recorded to the purchase price allocation of certain prior acquisitions completed within the last twelve months as permitted by Accounting Standards Codification Topic 805 — Business Combinations (“ASC 805”). Such adjustments are presented in the “Other” category within the following two tables. The recorded purchase price for all acquisitions includes an estimation of the fair value of liabilities associated with any potential earn-out provisions. Subsequent changes in the fair value of earn-out obligations will be recorded in the Condensed Consolidated Statement of Income when incurred.

The fair value of earn-out obligations is based on the present value of the expected future payments to be made to the sellers of the acquired businesses in accordance with the provisions outlined in the respective purchase agreements. In determining fair value, the acquired business’s future performance is estimated using financial projections developed by management for the acquired business and reflects market participant assumptions regarding revenue growth and/or profitability. The expected future payments are estimated on the basis of the earn-out formula and performance targets specified in each purchase agreement compared to the associated financial projections. These payments are then discounted to present value using a risk-adjusted rate that takes into consideration the likelihood that the forecasted earn-out payments will be made.

Based on the acquisition date and the complexity of the underlying valuation work, certain amounts included in the Company’s Condensed Consolidated Financial Statements may be provisional and thus subject to further adjustments within the permitted measurement period, as defined in ASC 805. For the nine months ended September 30, 2018, adjustments were made within the permitted measurement period that resulted in an increase in the aggregate purchase price of the affected acquisitions of $21.4 thousand relating to the assumption of certain liabilities. These measurement period adjustments have been reflected as current period adjustments in the nine months ended September 30, 2018 in accordance with the guidance in ASU 2015-16 “Business Combinations.” The measurement period adjustments primarily impacted goodwill, with no effect on earnings or cash in the current period.

Cash paid for acquisitions was $265.9 million in the nine-month period ended September 30, 2018. We completed eighteen acquisitions (excluding book of business purchases) in the nine-month period ended September 30, 2018. We completed six acquisitions (excluding book of business purchases) in the nine-month period ended September 30, 2017.

The following table summarizes the purchase price allocations made as of the date of each acquisition for current year acquisitions and adjustments made during the measurement period for prior year acquisitions. During the measurement periods, the Company will adjust assets or liabilities if new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have resulted in the recognition of those assets and liabilities as of that date. These adjustments are made in the period in which the amounts are determined and the current period income effect of such adjustments will be calculated as if the adjustments had been completed as of the acquisition date.



(in thousands)
Name	Business segment	Effective date of acquisition	Cash paid		Other payable		Recorded earn-out payable		Net assets acquired		Maximum potential earn- out payable
Opus Advisory Group, LLC (Opus)	Retail	February 1, 2018	$	20,400	$	200	$	2,384	$	22,984	$	3,600
Kerxton Insurance Agency, Inc. (Kerxton)	Retail	March 1, 2018	13,177		1,490		2,080		16,747		2,920
Automotive Development Group, LLC (ADG)	Retail	May 1, 2018	29,471		559		17,545		47,575		20,000
Servco Pacific, Inc. (Servco)	Retail	June 1, 2018	76,551		—		916		77,467		7,000
Tower Hill Prime Insurance Company (Tower Hill)	National Programs	July 1, 2018	20,300		—		2,628		22,928		7,700
Health Special Risk, Inc. (HSR)	National Programs	July 1, 2018	20,132		—		1,991		22,123		9,000
Professional Disability Associates, LLC (PDA)	Services	July 1, 2018	15,025		—		9,818		24,843		17,975
Finance & Insurance Resources, Inc. (F&I)	Retail	September 1, 2018	44,940		410		9,121		54,471		19,500
Other	Various	Various	25,894		680		5,234		31,808		10,200
Total			$	265,890	$	3,339	$	51,717	$	320,946	$	97,895

The following table summarizes the estimated fair values of the aggregate assets and liabilities acquired as of the date of each acquisition and adjustments made during the measurement period of the prior year acquisitions.



(in thousands)	Opus		Kerxton			ADG		Servco			Tower Hill		HSR			PDA			F&I		Other			Total
Cash	$	—	$	—		$	—	$	8,189		$	—	$	3,114		$	—		$	—	$	—		$	11,303
Other current assets	—		—			1,500		8,075			—		818			1,762			999		253			13,407
Fixed assets	11		10			67		178			$	—	$	124		$	309		$	34	$	99		$	832
Goodwill	17,944		13,417			36,236		53,901			—		18,737			17,273			36,806		20,245			214,559
Purchased customer accounts	5,008		4,712			9,751		16,902			22,928		5,516			7,700			16,611		12,653			101,781
Non-compete agreements	21		22			21		1			—		65			82			21		273			506
Other assets	—		—			—		1,528			—		21			(787		)	—		—			762
Total assets acquired	22,984		18,161			47,575		88,774			22,928		28,395			26,339			54,471		33,523			343,150
Other current liabilities	—		(1,414		)	—		(11,307		)	—		(5,930		)	(1,273		)	—		(1,715		)	(21,639		)
Other liabilities	—		—			—		—			—		(342		)	(223		)	—		—			(565		)
Total liabilities assumed	—		(1,414		)	—		(11,307		)	—		(6,272		)	(1,496		)	—		(1,715		)	(22,204		)
Net assets acquired	$	22,984	$	16,747		$	47,575	$	77,467		$	22,928	$	22,123		$	24,843		$	54,471	$	31,808		$	320,946

The weighted average useful lives for the acquired amortizable intangible assets are as follows: purchased customer accounts, 15 years; and non-compete agreements, 5 years.

Goodwill of $214.6 million, which is net of any opening balance sheet adjustments within the allowable measurement period, was allocated to the Retail, National Programs, Wholesale Brokerage and Services Segments in the amounts of $173.0 million, $18.7 million, $5.5 million and $17.3 million, respectively. Of the total goodwill of $214.6 million, the amount currently deductible for income tax purposes is $162.9 million and the remaining $51.7 million relates to the recorded earn-out payables and will not be deductible until it is earned and paid.

For the acquisitions completed during 2018, the results of operations since the acquisition dates have been combined with those of the Company. The total revenues from the acquisitions completed through September 30, 2018, included in the Condensed Consolidated Statement of Income for the nine months ended September 30, 2018, was $29.2 million. The income before income taxes, including the intercompany cost of capital charge, from the acquisitions completed through September 30, 2018, included in the Condensed Consolidated Statement of Income for the nine months ended September 30, 2018, was $1.8 million. If the acquisitions had occurred as of the beginning of the respective periods, the Company’s results of operations would be as shown in the following table. These unaudited pro forma results are not necessarily indicative of the actual results of operations that would have occurred had the acquisitions actually been made at the beginning of the respective periods.



(UNAUDITED)	Three months ended September 30,				Nine months ended September 30,
(in thousands, except per share data)	2018		2017		2018		2017
Total revenues	$	533,038	$	499,846	$	1,547,556	$	1,477,640
Income before income taxes	$	143,402	$	130,171	$	372,204	$	360,034
Net income	$	106,742	$	79,422	$	278,551	$	222,407
Net income per share:
Basic	$	0.38	$	0.28	$	1.01	$	0.79
Diluted	$	0.38	$	0.28	$	0.99	$	0.78
Weighted average number of shares outstanding:
Basic	271,008		272,692		270,423		273,184
Diluted	275,282		277,786		275,614		278,022

As of September 30, 2018 and 2017, the fair values of the estimated acquisition earn-out payables were re-evaluated and measured at fair value on a recurring basis using unobservable inputs (Level 3) as defined in ASC 820-Fair Value Measurement. The resulting additions, payments, and net changes, as well as the interest expense accretion on the estimated acquisition earn-out payables, for the three and nine months ended September 30, 2018 and 2017, were as follows:



	Three months ended September 30,						Nine months ended September 30,
(in thousands)	2018			2017			2018			2017
Balance as of the beginning of the period	$	52,540		$	57,943		$	36,175		$	63,821
Additions to estimated acquisition earn-out payables	29,646			1,050			51,717			1,332
Payments for estimated acquisition earn-out payables	(16,521		)	(23,511		)	(25,112		)	(39,288		)
Subtotal	65,665			35,482			62,780			25,865
Net change in earnings from estimated acquisition earn-out payables:
Change in fair value on estimated acquisition earn-out payables	(928		)	(1,784		)	945			6,402
Interest expense accretion	571			476			1,583			1,907
Net change in earnings from estimated acquisition earn-out payables	(357		)	(1,308		)	2,528			8,309
Balance as of September 30,	$	65,308		$	34,174		$	65,308		$	34,174

Of the $65.3 million estimated acquisition earn-out payables as of September 30, 2018, $14.1 million was recorded as accounts payable and $51.2 million was recorded as other non-current liabilities. As of September 30, 2018, the maximum future acquisition contingency payments related to all acquisitions was $151.6 million, inclusive of the $65.3 million estimated acquisition earn-out payables as of September 30, 2018. Included within the additions to estimated acquisition earn-out payables are any adjustments to opening balance sheet items within the allowable measurement period, which may therefore differ from previously reported amounts.

Goodwill

9 Months Ended

Sep. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

Goodwill is subject to at least an annual assessment for impairment by applying a fair value-based test. The Company completed its most recent annual assessment as of November 30, 2017, and identified no impairment as a result of the evaluation.

The changes in the carrying value of goodwill by reportable segment for the nine months ended September 30, 2018 are as follows:



(in thousands)	Retail		National Programs			Wholesale Brokerage		Services		Total
Balance as of January 1, 2018	$	1,386,248	$	908,472		$	286,098	$	135,261	$	2,716,079
Goodwill of acquired businesses	173,025		18,737			5,524		17,273		214,559
Goodwill disposed of relating to sales of businesses	—		(1,004		)	—		—		(1,004		)
Balance as of September 30, 2018	$	1,559,273	$	926,205		$	291,622	$	152,534	$	2,929,634

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Amortizable Intangible Assets

9 Months Ended

Sep. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Amortizable Intangible Assets

Amortizable intangible assets at September 30, 2018 and December 31, 2017 consisted of the following:



	September 30, 2018								December 31, 2017
(in thousands)	Gross carrying value		Accumulated amortization			Net carrying value		Weighted average life (years)⁽¹⁾	Gross carrying value		Accumulated amortization			Net carrying value		Weighted average life (years)⁽¹⁾
Purchased customer accounts	$	1,565,186	$	(886,229	)	$	678,957	15.0	$	1,464,274	$	(824,584	)	$	639,690	15.0
Non-compete agreements	30,753		(29,484		)	1,269		6.7	30,287		(28,972		)	1,315		6.8
Total	$	1,595,939	$	(915,713	)	$	680,226		$	1,494,561	$	(853,556	)	$	641,005


(1)	Weighted average life calculated as of the date of acquisition.

Amortization expense for amortizable intangible assets for the years ending December 31, 2018, 2019, 2020, 2021 and 2022 is estimated to be $84.7 million, $83.4 million, $76.0 million, $72.7 million, and $68.3 million, respectively.

Long-Term Debt

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Long-Term Debt

Long-term debt at September 30, 2018 and December 31, 2017 consisted of the following:



(in thousands)	September 30, 2018			December 31, 2017
Current portion of long-term debt:
Current portion of 5-year term loan facility expires June 28, 2022	$	30,000		$	20,000
4.500% senior notes, Series E, quarterly interest payments, balloon due September 2018	—			100,000
Total current portion of long-term debt	30,000			120,000
Long-term debt:
Note agreements:
4.200% senior notes, semi-annual interest payments, net of the unamortized discount, balloon due 2024	499,062			498,943
Total notes	499,062			498,943
Credit agreements:
5-year term-loan facility, periodic interest and principal payments, LIBOR plus up to 1.750%, expires June 28, 2022	340,000			365,000
5-year revolving-loan facility, periodic interest payments, LIBOR plus up to 1.500%, plus commitment fees up to 0.250%, expires June 28, 2022	—			—
Total credit agreements	340,000			365,000
Debt issuance costs (contra)	(6,701		)	(7,802		)
Total long-term debt less unamortized discount and debt issuance costs	832,361			856,141
Current portion of long-term debt	30,000			120,000
Total debt	$	862,361		$	976,141

On December 22, 2006, the Company entered into a Master Shelf and Note Purchase Agreement (the “Master Agreement”) with a national insurance company. The initial issuance of notes under the Master Agreement occurred on December 22, 2006, through the issuance of $25.0 million in Series C Senior Notes due December 22, 2016, with a fixed interest rate of 5.660% per year. On February 1, 2008, $25.0 million in Series D Senior Notes due January 15, 2015, with a fixed interest rate of 5.370% per year, were issued. On September 15, 2011, and pursuant to a Confirmation of Acceptance, dated January 21, 2011, in connection with the Master Agreement, $100.0 million in Series E Senior Notes were issued with a maturity date of September 15, 2018, with a fixed interest rate of 4.500% per year. The Series E Senior Notes were issued for the sole purpose of retiring existing Senior Notes. On January 15, 2015 the Series D Senior Notes were redeemed at maturity using cash proceeds to pay off the principal of $25.0 million plus any remaining accrued interest. On December 22, 2016, the Series C Senior Notes were redeemed at maturity using cash proceeds to pay off the principal of $25.0 million plus any remaining accrued interest. On May 10, 2018, the principal balance of $100.0 million from the Series E Senior Notes was paid in full, along with accrued interest of $0.7 million and a prepayment premium of $0.7 million. As of September 30, 2018, there was no outstanding debt balance issued under the provisions of the Master Agreement.

On June 28, 2017, the Company entered into an amended and restated credit agreement (the “Amended and Restated Credit Agreement”) with the lenders named therein, JPMorgan Chase Bank, N.A. as administrative agent and certain other banks as co-syndication agents and co-documentation agents. The Amended and Restated Credit Agreement amended and restated the credit agreement dated April 17, 2014, among such parties (the “Original Credit Agreement”). The Amended and Restated Credit Agreement extends the applicable maturity date of the existing revolving credit facility (the “Facility”) of $800.0 million to June 28, 2022 and re-evidences unsecured term loans at $400.0 million while also extending the applicable maturity date to June 28, 2022. The term loan principal amortization schedule was reset with payments due quarterly. At the time of the execution of the Amended and Restated Credit Agreement, $67.5 million of principal from the original unsecured term loans was repaid using operating cash balances, and the Company added an additional $2.8 million in debt issuance costs related to the Facility to the Consolidated Balance Sheet. The Company also expensed to the Consolidated Statements of Income $0.2 million of debt issuance costs related to the Original Credit Agreement due to certain lenders exiting prior to the modified agreement, while also carrying forward $1.6 million on the Consolidated Balance Sheet the unamortized portion of the Original Credit Agreement debt issuance costs which will amortize over the term of the Amended and Restated Credit Agreement. Either or both of the revolving credit facility and the term loans may be extended for two additional one-year periods at the Company’s request and at the discretion of the respective lenders. Interest and facility fees in respect to the Credit Facility are based upon the better of the Company’s net debt leverage ratio or a non-credit enhanced senior unsecured long-term debt rating. Based upon the Company’s net debt leverage ratio, the rates of interest charged on the term loan are 1.000% to 1.750%, and the revolving loan is 0.850% to 1.500% above the adjusted LIBOR rate for outstanding amounts drawn. There are fees included in the facility which include a facility fee based upon the revolving credit commitments of the lenders (whether used or unused) at a rate of 0.150% to 0.250% and letter of credit fees based upon the amounts of outstanding secured or unsecured letters of credit. The Amended and

Restated Credit Agreement includes various covenants, limitations and events of default customary for similar facilities for similarly rated borrowers. On June 30, 2018, a scheduled principal payment of $5.0 million was satisfied per the terms of the Amended and Restated Credit Agreement. On September 30, 2018, a scheduled principal payment of $5.0 million was satisfied per the terms of the Amended and Restated Credit Agreement. As of September 30, 2018, there was an outstanding debt balance issued under the terms of the Amended and Restated Credit Agreement of $370.0 million with no borrowings outstanding against the revolving loan. Per the terms of the Amended and Restated Credit Agreement, a scheduled principal payment of $5.0 million is due December 31, 2018.

On September 18, 2014, the Company issued $500.0 million of 4.200% unsecured Senior Notes due in 2024. The Senior Notes were given investment grade ratings of BBB-/Baa3 with a stable outlook. The notes are subject to certain covenant restrictions and regulations which are customary for credit rated obligations. At the time of funding, the proceeds were offered at a discount of the original note amount which also excluded an underwriting fee discount. The net proceeds received from the issuance were used to repay the outstanding balance of $475.0 million on the revolving Credit Facility and for other general corporate purposes. As of September 30, 2018 and December 31, 2017, there was an outstanding debt balance of $500.0 million exclusive of the associated discount balance.

The Master Agreement and the Amended and Restated Credit Agreement require the Company to maintain certain financial ratios and comply with certain other covenants. The Company was in compliance with all such covenants as of September 30, 2018 and December 31, 2017.

The 30-day Adjusted LIBOR Rate as of September 30, 2018 was 2.125%.

Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities

9 Months Ended

Sep. 30, 2018

Supplemental Cash Flow Elements [Abstract]

Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities

Brown & Brown's cash paid during the period for interest and income taxes are summarized as follows:



	Nine months ended September 30,
(in thousands)	2018		2017
Cash paid during the period for:
Interest	$	32,896	$	32,504
Income taxes	$	21,380	$	110,853

Brown & Brown’s significant non-cash investing and financing activities are summarized as follows:



	Nine months ended September 30,
(in thousands)	2018		2017
Other payable issued for purchased customer accounts	$	3,339	$	11,395
Estimated acquisition earn-out payables and related charges	$	51,717	$	1,332

Our restricted cash balance is composed of funds held in separate premium trust accounts as required by state law or, in some cases, by agreement with our carrier partners. The following is a reconciliation of cash and cash equivalents inclusive of restricted cash as of September 30, 2018 and 2017.



	Balance as of September 30,
(in thousands)	2018		2017
Table to reconcile cash and cash equivalents inclusive of restricted cash
Cash and cash equivalents	$	422,971	$	546,520
Restricted cash	301,716		276,687
Total cash and cash equivalents inclusive of restricted cash at the end of the period	$	724,687	$	823,207

The following is a reconciliation of cash and cash equivalents inclusive of restricted cash as of December 31, 2017 and 2016.



	Balance as of December 31,
(in thousands)	2017		2016
Table to reconcile cash and cash equivalents inclusive of restricted cash
Cash and cash equivalents	$	573,383	$	515,646
Restricted cash	250,705		265,637
Total cash and cash equivalents inclusive of restricted cash at the end of the period	$	824,088	$	781,283

In the preparation of the Statement of Cash Flows in this Quarterly Report on Form 10-Q, beginning balance sheet balances for 2018 were adjusted to reflect the modified retrospective adoption of Accounting Standards Update No.2014-09, “Revenue from Contracts with Customers” and Accounting Standards Codification Topic 340 - Other Assets and Deferred Cost, thereby reflecting in the Statement of Cash Flows the change in operating assets and liabilities for the period, excluding the initial impact of adoption of these new accounting standards. Refer to Note 2 in the "Recently Adopted Accounting Standards" for the initial impact of adoption of these new accounting standards.

Legal and Regulatory Proceedings	9 Months Ended
Legal and Regulatory Proceedings	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Legal and Regulatory Proceedings	Legal and Regulatory Proceedings The Company is involved in numerous pending or threatened proceedings by or against Brown & Brown, Inc. or one or more of its subsidiaries that arise in the ordinary course of business. The damages that may be claimed against the Company in these various proceedings are in some cases substantial, including in certain instances claims for punitive or extraordinary damages. Some of these claims and lawsuits have been resolved; others are in the process of being resolved and others are still in the investigation or discovery phase. The Company will continue to respond appropriately to these claims and lawsuits and to vigorously protect its interests. During the first quarter of 2017, the Company was successful in settling a lawsuit it had brought against certain former employees of Brown & Brown, their employer, AssuredPartners, Inc. ("AssuredPartners") and certain key executives of AssuredPartners. The settlement included a payment of $20.0 million by AssuredPartners to Brown & Brown in exchange for releasing certain individuals from restrictive covenants in the employment contracts they had signed with the Company and provides protection for current Brown & Brown teammates from continued solicitation for employment by AssuredPartners. The proceeds of the settlement were received in March 2017 and were recorded in the other income line in the Condensed Consolidated Statement of Income. We continue to assess certain litigation and claims to determine the amounts, if any, that management believes will be paid as a result of such claims and litigation and, therefore, additional losses may be accrued and paid in the future, which could adversely impact the Company’s operating results, cash flows and overall liquidity. The Company maintains third-party insurance policies to provide coverage for certain legal claims, in an effort to mitigate its overall exposure to unanticipated claims or adverse decisions. However, as (i) one or more of the Company’s insurance carriers could take the position that portions of these claims are not covered by the Company’s insurance, (ii) to the extent that payments are made to resolve claims and lawsuits, applicable insurance policy limits are eroded and (iii) the claims and lawsuits relating to these matters are continuing to develop, it is possible that future results of operations or cash flows for any particular quarterly or annual period could be materially affected by unfavorable resolutions of these matters. Based upon the AM Best Company ratings of these third-party insurers, management does not believe there is a substantial risk of an insurer’s material non-performance related to any current insured claims. On the basis of current information, the availability of insurance and legal advice, in management’s opinion, the Company is not currently involved in any legal proceedings which, individually or in the aggregate, would have a material adverse effect on its financial condition, operations and/or cash flows.

Segment Information

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Segment Information

Brown & Brown’s business is divided into four reportable segments: (1) the Retail Segment, which provides a broad range of insurance products and services to commercial, public and quasi-public entities, and to professional and individual customers, (2) the National Programs Segment, which acts as a MGA, provides professional liability and related package products for certain professionals, a range of insurance products for individuals, flood coverage, and targeted products and services designated for specific industries, trade groups, governmental entities and market niches, all of which are delivered through nationwide networks of independent agents, and Brown & Brown retail agents, (3) the Wholesale Brokerage Segment, which markets and sells excess and surplus commercial and personal lines insurance, primarily through independent agents and brokers, as well as Brown & Brown retail agents, and (4) the Services Segment, which provides insurance-related services, including third-party claims administration and comprehensive medical utilization management services in both the workers’ compensation and all-lines liability arenas, as well as Medicare Set-aside services, Social Security disability and Medicare benefits advocacy services and claims adjusting services.

Brown & Brown conducts all of its operations within the United States of America, except for a wholesale brokerage operation based in London, England, retail operations in Bermuda and the Cayman Islands, and national programs operations in Canada. These operations earned $3.7 million and $3.9 million of total revenues for the three months ended September 30, 2018 and 2017, respectively. These operations earned $11.3 million and $11.1 million of total revenues for the nine months ended September 30, 2018 and 2017, respectively. Long-lived assets held outside of the United States as of September 30, 2018 and 2017 were not material.

The accounting policies of the reportable segments are the same as those described in Note 1 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2017. The Company evaluates the performance of its segments based upon revenues and income before income taxes. Inter-segment revenues are eliminated.

Summarized financial information concerning the Company’s reportable segments is shown in the following tables. The “Other” column includes any income and expenses not allocated to reportable segments, corporate-related items, including the intercompany interest expense charge to the reporting segment.



	Three months ended September 30, 2018
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	261,087	$	143,519	$	78,009	$	48,105	$	130		$	530,850
Investment income	$	1	$	138	$	44	$	51	$	485		$	719
Amortization	$	10,754	$	6,736	$	2,878	$	1,269	$	—		$	21,637
Depreciation	$	1,236	$	1,346	$	385	$	393	$	1,899		$	5,259
Interest expense	$	7,468	$	6,147	$	1,233	$	846	$	(6,731	)	$	8,963
Income before income taxes	$	61,224	$	46,707	$	23,614	$	6,988	$	3,967		$	142,500
Total assets	$	4,651,080	$	2,933,465	$	1,272,795	$	448,027	$	(3,502,561	)	$	5,802,806
Capital expenditures	$	1,467	$	2,420	$	895	$	366	$	4,321		$	9,469



	Three months ended September 30, 2017
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	234,483	$	127,718	$	71,574	$	41,491	$	380		$	475,646
Investment income	$	3	$	124	$	—	$	72	$	292		$	491
Amortization	$	10,540	$	6,913	$	2,845	$	1,137	$	—		$	21,435
Depreciation	$	1,262	$	1,412	$	471	$	402	$	1,942		$	5,489
Interest expense	$	7,216	$	8,304	$	1,515	$	876	$	(8,518	)	$	9,393
Income before income taxes	$	54,950	$	32,203	$	21,219	$	7,910	$	8,137		$	124,419
Total assets	$	4,246,422	$	5,026,918	$	1,258,783	$	432,331	$	(3,550,177	)	$	7,414,277
Capital expenditures	$	844	$	1,357	$	214	$	364	$	1,270		$	4,049



	Nine months ended September 30, 2018
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	772,806	$	374,434	$	219,725	$	138,038	$	495		$	1,505,498
Investment income	$	2	$	384	$	125	$	160	$	1,380		$	2,051
Amortization	$	31,498	$	19,383	$	8,537	$	3,543	$	—		$	62,961
Depreciation	$	3,746	$	4,087	$	1,238	$	1,183	$	6,156		$	16,410
Interest expense	$	21,377	$	20,019	$	4,039	$	2,023	$	(18,772	)	$	28,686
Income before income taxes	$	175,984	$	91,809	$	55,544	$	23,889	$	14,625		$	361,851
Total assets	$	4,651,080	$	2,933,465	$	1,272,795	$	448,027	$	(3,502,561	)	$	5,802,806
Capital expenditures	$	5,828	$	7,313	$	1,762	$	798	$	13,158		$	28,859



	Nine months ended September 30, 2017
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	712,739	$	342,576	$	208,812	$	122,397	$	20,507		$	1,407,031
Investment income	$	6	$	279	$	—	$	224	$	576		$	1,085
Amortization	$	31,704	$	20,664	$	8,621	$	3,412	$	1		$	64,402
Depreciation	$	3,975	$	4,975	$	1,438	$	1,191	$	5,663		$	17,242
Interest expense	$	23,918	$	27,257	$	4,803	$	2,783	$	(29,812	)	$	28,949
Income before income taxes	$	151,783	$	68,127	$	56,569	$	22,480	$	44,429		$	343,388
Total assets	$	4,246,422	$	5,026,918	$	1,258,783	$	432,331	$	(3,550,177	)	$	7,414,277
Capital expenditures	$	3,384	$	3,885	$	1,606	$	856	$	3,166		$	12,897

Investments

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Investments

At September 30, 2018, the Company’s amortized cost and fair values of fixed maturity securities are summarized as follows:



(in thousands)	Cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	21,722	$	3	$	(462	)	$	21,263
Corporate debt	622		—		(2		)	620
Total	$	22,344	$	3	$	(464	)	$	21,883

At September 30, 2018, the Company held $21.3 million in fixed income securities composed of U.S. Treasury securities, securities issued by U.S. Government agencies and municipalities, and $0.6 million issued by corporations with investment grade ratings. Of that total, $4.7 million is classified as short-term investments on the Condensed Consolidated Balance Sheet as maturities are less than one-year, which also includes $8.1 million that is related to time deposits held with various financial institutions.

For securities in a loss position, the following table shows the investments’ gross unrealized loss and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2018:



	Less than 12 Months					12 Months or More					Total
(in thousands)	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	8,237	$	(104	)	$	12,727	$	(358	)	$	20,964	$	(462	)
Corporate debt	620		(2		)	—		—			620		(2		)
Total	$	8,857	$	(106	)	$	12,727	$	(358	)	$	21,584	$	(464	)

The unrealized losses were caused by interest rate increases. At September 30, 2018, the Company had 23 securities in an unrealized loss position. The corporate securities are highly rated securities with no indicators of potential impairment. Based on the ability and intent of the Company to hold these investments until recovery of fair value, which may be maturity, the bonds were not considered to be other-than-temporarily impaired at September 30, 2018.

At December 31, 2017, the Company’s amortized cost and fair values of fixed maturity securities are summarized as follows:



(in thousands)	Cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	29,970	$	—	$	(206	)	$	29,764
Corporate debt	1,072		12		—			1,084
Total	$	31,042	$	12	$	(206	)	$	30,848

At December 31, 2017, the Company held $29.8 million in fixed income securities composed of U.S. Treasury securities, securities issued by U.S. Government agencies and municipalities, and $1.1 million issued by corporations with investment grade ratings. Of that total, $16.9 million is classified as short-term investments on the Condensed Consolidated Balance Sheet as maturities are less than one-year, which also includes $8.1 million that is related to time deposits held with various financial institutions.



	Less than 12 Months					12 Months or More					Total
(in thousands)	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	17,919	$	(157	)	$	11,845	$	(49	)	$	29,764	$	(206	)
Corporate debt	400		—			—		—			400		—
Total	$	18,319	$	(157	)	$	11,845	$	(49	)	$	30,164	$	(206	)

The unrealized losses from corporate issuers were caused by interest rate increases. At December 31, 2017, the Company had 27 securities in an unrealized loss position. The corporate securities are highly rated securities with no indicators of potential impairment. Based on the ability and intent of the Company to hold these investments until recovery of fair value, which may be maturity, the bonds were not considered to be other-than-temporarily impaired at December 31, 2017.

The amortized cost and estimated fair value of the fixed maturity securities at September 30, 2018 by contractual maturity are set forth below:



(in thousands)	Amortized cost		Fair value
Years to maturity:
Due in one year or less	$	4,771	$	4,732
Due after one year through five years	17,341		16,920
Due after five years	232		231
Total	$	22,344	$	21,883

The amortized cost and estimated fair value of the fixed maturity securities at December 31, 2017 by contractual maturity are set forth below:



(in thousands)	Amortized cost		Fair value
Years to maturity:
Due in one year or less	$	16,934	$	16,899
Due after one year through five years	13,876		13,708
Due after five years	232		241
Total	$	31,042	$	30,848

The expected maturities in the foregoing table may differ from the contractual maturities because certain borrowers have the right to call or prepay obligations with or without penalty.

Proceeds from the sales and maturity of the Company’s investment in fixed maturity securities were $17.0 million. This along with maturing time deposits yielded total cash proceeds from the sale of investments of $17.6 million in the period of January 1, 2018 to September 30, 2018. These proceeds were used to purchase additional fixed maturity securities and time deposits. The gains and losses realized on those sales for the period from January 1, 2018 to September 30, 2018 were insignificant.

Realized gains and losses are reported on the Condensed Consolidated Statements of Income, with the cost of securities sold determined on a specific identification basis.

At September 30, 2018, investments with a fair value of approximately $4.0 million were on deposit with state insurance departments to satisfy regulatory requirements.

Losses and Loss Adjustment Reserve

9 Months Ended

Sep. 30, 2018

Reinsurance Disclosures [Abstract]

Losses and Loss Adjustment Reserve

Although the reinsurers are liable to the Company for amounts reinsured, our subsidiary, Wright National Flood Insurance Company (“Wright Flood”) remains primarily liable to its policyholders for the full amount of the policies written whether or not the reinsurers meet their obligations to the Company when they become due. The effects of reinsurance on premiums written and earned are as follows:



	Period from January 1, 2018 to September 30, 2018
(in thousands)	Written			Earned
Direct premiums	$	469,078		$	445,140
Ceded premiums	(469,065		)	(445,127		)
Net premiums	$	13		$	13

All premiums written by Wright Flood under the National Flood Insurance Program are 100% ceded to the Federal Emergency Management Agency, or FEMA, for which Wright Flood received a 30.9% expense allowance from January 1, 2018 through September 30, 2018. For the period from January 1, 2018 through September 30, 2018, the Company ceded $467.7 million of written premiums.

Effective April 1, 2014, Wright Flood is also a party to a quota share agreement whereby it cedes 100% of its gross excess flood premiums, excluding fees, to Arch Reinsurance Company and receives a 30.5% commission. Wright Flood ceded $1.4 million for the period from January 1, 2018 through September 30, 2018. As of September 30, 2018, Wright Flood had $2.1 million in paid excess flood losses, $92,519 in loss adjustment expenses, case reserves of $161,758 and $1,500 in allocated loss adjustment expense ("ALAE") case reserves and incurred but not reported of $485,000.

Wright Flood also ceded 100% of the homeowners, private passenger auto liability, and other liability occurrence to Stillwater Insurance Company, formerly known as Fidelity National Insurance Company. This business is in runoff. Therefore, only loss data exists on this business. As of September 30, 2018, no ceded unpaid losses and loss adjustment expenses or incurred but not reported expenses for homeowners, private passenger auto liability and other liability occurrence existed.

As of September 30, 2018 the Condensed Consolidated Balance Sheet contained reinsurance recoverable of $98.5 million, prepaid reinsurance premiums of $345.0 million and recoverable on paid losses of $40.9 thousand. There was no net activity in the reserve for losses and loss adjustment expense during the period January 1, 2018 through September 30, 2018, as Wright Flood’s direct premiums written were 100% ceded to two reinsurers. The balance of the reserve for losses and loss adjustment expense, excluding related reinsurance recoverable, as of September 30, 2018 was $98.5 million.

Statutory Financial Information	9 Months Ended
Statutory Financial Information	Sep. 30, 2018
Statutory Accounting Practices [Abstract]
Statutory Financial Information	Statutory Financial DataWright Flood maintains capital in excess of the minimum statutory amount of $7.5 million as required by regulatory authorities. The unaudited statutory capital and surplus of Wright Flood was $22.8 million at September 30, 2018 and $28.7 million as of December 31, 2017. For the period from January 1, 2018 through September 30, 2018, Wright Flood generated statutory net income of $4.3 million. For the period from January 1, 2017 through December 31, 2017, Wright Flood generated statutory net income of $4.8 million.

Subsidiary Dividend Restrictions	9 Months Ended
Subsidiary Dividend Restrictions	Sep. 30, 2018
Dividend Restrictions [Line Items]
Subsidiary Dividend Restrictions	Under the insurance regulations of Texas, where Wright Flood is incorporated, the maximum amount of ordinary dividends that Wright Flood can pay to shareholders in a rolling twelve-month period is limited to the greater of 10% of statutory adjusted capital and surplus as shown on Wright Flood’s last annual statement on file with the superintendent of the Texas Department of Insurance or 100% of adjusted net income. There was no dividend payout in 2017 and the maximum dividend payout that may be made in 2018 without prior approval is $4.8 million.

Shareholders' Equity	9 Months Ended
Shareholders' Equity	Sep. 30, 2018
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity On November 14, 2017, the Company entered into an accelerated share repurchase agreement (“ASR”) with an investment bank to purchase an aggregate $75.0 million of the Company’s common stock. As part of the ASR, the Company received an initial delivery of 1,290,486 shares of the Company’s common stock with a fair market value of approximately $63.8 million. At maturity of the program on February 9, 2018, the Company received an additional 168,227 shares, relating to the remaining balance of the ASR of $11.2 million. The Company received a total of 1,458,713 shares of Company’s common stock under this ASR. Under the authorization from the Company’s Board of Directors, shares may be purchased from time to time, at the Company’s discretion and subject to the availability of stock, market conditions, the trading price of the stock, alternative uses for capital, the Company’s financial performance and other potential factors. These purchases may be carried out through open market purchases, block trades, accelerated share repurchase plans of up to $100.0 million each (unless otherwise approved by the Board of Directors), negotiated private transactions or pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934. After completion of the latest ASR transaction, the Company has approval to repurchase up to $227.5 million, in the aggregate, of the Company’s outstanding common stock. See Part II, Item 2 "Unregistered Sale of Equity Securities and Use of Proceeds" for details. On March 28, 2018, we effected a 2-for-1 stock split (the “Stock Split”). As a result of the Stock Split, every share of common stock outstanding as of close of business on March 14, 2018 received an additional share of common stock, increasing the number of outstanding shares of common stock from approximately 138 million shares to approximately 276 million shares. The number of authorized shares of our common stock increased from 280 million shares to 560 million shares. No fractional shares were issued in connection with the Stock Split. Par value of the Company’s common stock was unchanged as a result of the Stock Split remaining at $0.10 per share. The number of shares of common stock reserved or subject to outstanding grants, the exercise or purchase prices applicable to such outstanding grants and subscriptions, and certain grant limitations under our 1990 Employee Stock Purchase Plan, Performance Stock Plan and 2010 Stock Incentive Plan were adjusted as a result of the Stock Split, as required under the terms of those plans. Treasury shares were not adjusted for the Stock Split. All other shares and per share data included within this Quarterly Report on Form 10-Q, including our Condensed Consolidated Financial Statements and related footnotes, have been adjusted to account for the effect of the Stock Split.

Income Taxes (Notes)	9 Months Ended
Income Taxes (Notes)	Sep. 30, 2018
Income Tax Policy [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	Shareholders’ Equity On November 14, 2017, the Company entered into an accelerated share repurchase agreement (“ASR”) with an investment bank to purchase an aggregate $75.0 million of the Company’s common stock. As part of the ASR, the Company received an initial delivery of 1,290,486 shares of the Company’s common stock with a fair market value of approximately $63.8 million. At maturity of the program on February 9, 2018, the Company received an additional 168,227 shares, relating to the remaining balance of the ASR of $11.2 million. The Company received a total of 1,458,713 shares of Company’s common stock under this ASR. Under the authorization from the Company’s Board of Directors, shares may be purchased from time to time, at the Company’s discretion and subject to the availability of stock, market conditions, the trading price of the stock, alternative uses for capital, the Company’s financial performance and other potential factors. These purchases may be carried out through open market purchases, block trades, accelerated share repurchase plans of up to $100.0 million each (unless otherwise approved by the Board of Directors), negotiated private transactions or pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934. After completion of the latest ASR transaction, the Company has approval to repurchase up to $227.5 million, in the aggregate, of the Company’s outstanding common stock. See Part II, Item 2 "Unregistered Sale of Equity Securities and Use of Proceeds" for details. On March 28, 2018, we effected a 2-for-1 stock split (the “Stock Split”). As a result of the Stock Split, every share of common stock outstanding as of close of business on March 14, 2018 received an additional share of common stock, increasing the number of outstanding shares of common stock from approximately 138 million shares to approximately 276 million shares. The number of authorized shares of our common stock increased from 280 million shares to 560 million shares. No fractional shares were issued in connection with the Stock Split. Par value of the Company’s common stock was unchanged as a result of the Stock Split remaining at $0.10 per share. The number of shares of common stock reserved or subject to outstanding grants, the exercise or purchase prices applicable to such outstanding grants and subscriptions, and certain grant limitations under our 1990 Employee Stock Purchase Plan, Performance Stock Plan and 2010 Stock Incentive Plan were adjusted as a result of the Stock Split, as required under the terms of those plans. Treasury shares were not adjusted for the Stock Split. All other shares and per share data included within this Quarterly Report on Form 10-Q, including our Condensed Consolidated Financial Statements and related footnotes, have been adjusted to account for the effect of the Stock Split.

Subsequent Event (Notes)	3 Months Ended
Subsequent Event (Notes)	Sep. 30, 2018
Subsequent Event [Line Items]
Subsequent Events [Text Block]	NOTE 18· Subsequent Event On October 22, 2018, the Company entered into an asset purchase agreement (the "Agreement") with The Hays Group, Inc., a Minnesota corporation (“THG”); The Hays Group Of Wisconsin LLC, a Minnesota limited liability company (“THGW”); The Hays Benefits Group, LLC, a Minnesota limited liability company; PlanIT, LLC, a Minnesota limited liability company (“PlanIT”); The Hays Benefits Group of Wisconsin, LLC, a Minnesota limited liability company (“THBGW”), and The Hays Group of Illinois, LLC, a Minnesota limited liability company (“THGI”); and Claims Management of Missouri, LLC, a Missouri limited liability company (dba MMMA Claims Management) (“MMMA,” and together with THG, THGW, THBG and PlanIT, each a “Seller” and collectively, the “Sellers”), and THG, as the Sellers’ Representative (the “Sellers’ Representative”). The Agreement contemplates that the Company will purchase certain assets and assume certain liabilities, of the Sellers. The Company will pay a purchase price of $705.0 million, consisting of $605.0 million in cash and number of shares of common stock, par value $0.10, of the Company equal to $100.0 million (as valued at the average closing price on the New York Stock Exchange over the 30-day period prior to the closing of the Acquisition). In addition, the Company may pay additional consideration to the Sellers in the form of earn-out payments in the aggregate amount of up to $25.0 million in cash over three years, which is subject to certain conditions and the successful achievement of average annual EBITDA compound annual growth rate targets for the acquired business during 2019, 2020 and 2021. The Hays Group, Inc. was founded in 1994 providing employee benefits, property & casualty, and personal lines insurance and has grown to be the 22nd largest U.S. broker as measured by Business Insurance magazine. With headquarters in Minneapolis, The Hays Group, Inc. operates across twenty-one states, increasing our presence in the mid-west. This transaction will initially be funded through utilization of the revolving line of credit within our credit facility, details of which can be found in Note 8 to these financial statements.

Nature of Operations (Policies)	9 Months Ended
Nature of Operations (Policies)	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting	The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of recurring accruals) necessary for a fair presentation have been included. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the Notes thereto set forth in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017.The preparation of these financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, as well as disclosures of contingent assets and liabilities, at the date of the Condensed Consolidated Financial Statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates.
Recently Issued Accounting Pronouncements	Recently Issued Accounting PronouncementsIn February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)” (“ASU 2016-02”), which provides guidance for accounting for leases. Under ASU 2016-02, the Company will be required to recognize the assets and liabilities for the rights and obligations created by leased assets with initial maturities greater than one year. In July 2018, the FASB also issued ASU 2018-10 and ASU 2018-11 related to Topic 842. ASU 2018-10 narrows certain aspects of the guidance issued in the amendments within ASU 2016-02. ASU 2018-11 provides entities with an additional transition method to adopt ASU 2016-02. Under this new transition method, an entity initially applies ASU 2016-02 at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ASU 2016-02, along with ASU 2018-10 and ASU 2018-11, will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company continues to evaluate the impact of this pronouncement with the principal impact expected to be that the present value of the remaining lease payments will be presented as a liability on the balance sheet as well as an asset of similar value representing the “Right of Use” for those leased properties. The Company plans to adopt Topic 842 under the transition method provided by ASU 2018-11. The undiscounted contractual cash payments remaining on leased properties were $210.4 million as of December 31, 2017 as indicated in Note 13 of the Company's Form 10-K and $209.8 million as of September 30, 2018 as detailed in the Liquidity and Capital Resources section of this Quarterly Report on Form 10-Q.

Basis of Financial Reporting Recently Adopted Accounting Standards (Policies)

9 Months Ended

Sep. 30, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

New Accounting Pronouncements and Changes in Accounting Principles [Text Block]

Recently Adopted Accounting Standards

The following areas are impacted by the adoption of Topic 606:



(in thousands)	Balance at December 31, 2017		Adjustments due to the New Revenue Standard		Balance at January 1, 2018
Balance Sheet
Assets:
Premiums, commissions and fees receivable	$	546,402	$	153,058	$	699,460
Other current assets	47,864		52,680		100,544

Liabilities:
Premiums payable to insurance companies	685,163		12,107		697,270
Accounts payable	64,177		8,747		72,924
Accrued expenses and other liabilities	228,748		22,794		251,542
Deferred income taxes, net	256,185		44,575		300,760

Shareholders' Equity:
Retained earnings	2,456,599		117,515		2,574,114

The following table illustrates the impact of adopting the New Revenue Standard has had on our reported results in the unaudited condensed consolidated statement of income.



	Nine months ended September 30, 2018
(in thousands)	As reported		Impact of adopting the New Revenue Standard			Balances without the New Revenue Standard
Statement of Income
Revenues:
Commissions and fees	$	1,502,219	$	24,700		$	1,477,519

Expenses:
Employee compensation and benefits	790,902		(3,396		)	794,298
Other operating expenses	243,704		6,996			236,708
Income taxes	91,048		5,309			85,739

Net income	$	270,803	$	15,791		$	255,012

Net Income Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Reconciliation between Basic and Diluted Weighted Average Shares Outstanding



	For the three months ended September 30,						For the nine months ended September 30,
(in thousands, except per share data)	2018			2017			2018			2017
Net income	$	106,053		$	75,913		$	270,803		$	212,125
Net income attributable to unvested awarded performance stock	(2,716		)	(1,852		)	(6,185		)	(5,181		)
Net income attributable to common shares	$	103,337		$	74,061		$	264,618		$	206,944
Weighted average number of common shares outstanding – basic	278,132			279,512			276,744			280,024
Less unvested awarded performance stock included in weighted average number of common shares outstanding – basic	(7,124		)	(6,820		)	(6,321		)	(6,840		)
Weighted average number of common shares outstanding for basic net income per common share	271,008			272,692			270,423			273,184
Dilutive effect of stock options	4,274			5,094			5,191			4,838
Weighted average number of shares outstanding – diluted	275,282			277,786			275,614			278,022
Net income per share:
Basic	$	0.38		$	0.27		$	0.98		$	0.76
Diluted	$	0.38		$	0.27		$	0.96		$	0.74

Business Combinations (Tables)

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Purchase price allocation for current year acquisitions and adjustments made for prior year acquisitions



(in thousands)
Name	Business segment	Effective date of acquisition	Cash paid		Other payable		Recorded earn-out payable		Net assets acquired		Maximum potential earn- out payable
Opus Advisory Group, LLC (Opus)	Retail	February 1, 2018	$	20,400	$	200	$	2,384	$	22,984	$	3,600
Kerxton Insurance Agency, Inc. (Kerxton)	Retail	March 1, 2018	13,177		1,490		2,080		16,747		2,920
Automotive Development Group, LLC (ADG)	Retail	May 1, 2018	29,471		559		17,545		47,575		20,000
Servco Pacific, Inc. (Servco)	Retail	June 1, 2018	76,551		—		916		77,467		7,000
Tower Hill Prime Insurance Company (Tower Hill)	National Programs	July 1, 2018	20,300		—		2,628		22,928		7,700
Health Special Risk, Inc. (HSR)	National Programs	July 1, 2018	20,132		—		1,991		22,123		9,000
Professional Disability Associates, LLC (PDA)	Services	July 1, 2018	15,025		—		9,818		24,843		17,975
Finance & Insurance Resources, Inc. (F&I)	Retail	September 1, 2018	44,940		410		9,121		54,471		19,500
Other	Various	Various	25,894		680		5,234		31,808		10,200
Total			$	265,890	$	3,339	$	51,717	$	320,946	$	97,895

Estimated fair values of aggregate assets and liabilities acquired



(in thousands)	Opus		Kerxton			ADG		Servco			Tower Hill		HSR			PDA			F&I		Other			Total
Cash	$	—	$	—		$	—	$	8,189		$	—	$	3,114		$	—		$	—	$	—		$	11,303
Other current assets	—		—			1,500		8,075			—		818			1,762			999		253			13,407
Fixed assets	11		10			67		178			$	—	$	124		$	309		$	34	$	99		$	832
Goodwill	17,944		13,417			36,236		53,901			—		18,737			17,273			36,806		20,245			214,559
Purchased customer accounts	5,008		4,712			9,751		16,902			22,928		5,516			7,700			16,611		12,653			101,781
Non-compete agreements	21		22			21		1			—		65			82			21		273			506
Other assets	—		—			—		1,528			—		21			(787		)	—		—			762
Total assets acquired	22,984		18,161			47,575		88,774			22,928		28,395			26,339			54,471		33,523			343,150
Other current liabilities	—		(1,414		)	—		(11,307		)	—		(5,930		)	(1,273		)	—		(1,715		)	(21,639		)
Other liabilities	—		—			—		—			—		(342		)	(223		)	—		—			(565		)
Total liabilities assumed	—		(1,414		)	—		(11,307		)	—		(6,272		)	(1,496		)	—		(1,715		)	(22,204		)
Net assets acquired	$	22,984	$	16,747		$	47,575	$	77,467		$	22,928	$	22,123		$	24,843		$	54,471	$	31,808		$	320,946

Unaudited pro forma results

These unaudited pro forma results are not necessarily indicative of the actual results of operations that would have occurred had the acquisitions actually been made at the beginning of the respective periods.



(UNAUDITED)	Three months ended September 30,				Nine months ended September 30,
(in thousands, except per share data)	2018		2017		2018		2017
Total revenues	$	533,038	$	499,846	$	1,547,556	$	1,477,640
Income before income taxes	$	143,402	$	130,171	$	372,204	$	360,034
Net income	$	106,742	$	79,422	$	278,551	$	222,407
Net income per share:
Basic	$	0.38	$	0.28	$	1.01	$	0.79
Diluted	$	0.38	$	0.28	$	0.99	$	0.78
Weighted average number of shares outstanding:
Basic	271,008		272,692		270,423		273,184
Diluted	275,282		277,786		275,614		278,022

Additions, payments, and net changes, as well as interest expense accretion on estimated acquisition earn-out payables

The resulting additions, payments, and net changes, as well as the interest expense accretion on the estimated acquisition earn-out payables, for the three and nine months ended September 30, 2018 and 2017, were as follows:



	Three months ended September 30,						Nine months ended September 30,
(in thousands)	2018			2017			2018			2017
Balance as of the beginning of the period	$	52,540		$	57,943		$	36,175		$	63,821
Additions to estimated acquisition earn-out payables	29,646			1,050			51,717			1,332
Payments for estimated acquisition earn-out payables	(16,521		)	(23,511		)	(25,112		)	(39,288		)
Subtotal	65,665			35,482			62,780			25,865
Net change in earnings from estimated acquisition earn-out payables:
Change in fair value on estimated acquisition earn-out payables	(928		)	(1,784		)	945			6,402
Interest expense accretion	571			476			1,583			1,907
Net change in earnings from estimated acquisition earn-out payables	(357		)	(1,308		)	2,528			8,309
Balance as of September 30,	$	65,308		$	34,174		$	65,308		$	34,174

Goodwill (Tables)

9 Months Ended

Sep. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in Carrying Value of Goodwill by Operating Segment

nine months ended September 30, 2018 are as follows:



(in thousands)	Retail		National Programs			Wholesale Brokerage		Services		Total
Balance as of January 1, 2018	$	1,386,248	$	908,472		$	286,098	$	135,261	$	2,716,079
Goodwill of acquired businesses	173,025		18,737			5,524		17,273		214,559
Goodwill disposed of relating to sales of businesses	—		(1,004		)	—		—		(1,004		)
Balance as of September 30, 2018	$	1,559,273	$	926,205		$	291,622	$	152,534	$	2,929,634

Amortizable Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Amortizable Intangible Assets

Amortizable intangible assets at September 30, 2018 and December 31, 2017 consisted of the following:



	September 30, 2018								December 31, 2017
(in thousands)	Gross carrying value		Accumulated amortization			Net carrying value		Weighted average life (years)⁽¹⁾	Gross carrying value		Accumulated amortization			Net carrying value		Weighted average life (years)⁽¹⁾
Purchased customer accounts	$	1,565,186	$	(886,229	)	$	678,957	15.0	$	1,464,274	$	(824,584	)	$	639,690	15.0
Non-compete agreements	30,753		(29,484		)	1,269		6.7	30,287		(28,972		)	1,315		6.8
Total	$	1,595,939	$	(915,713	)	$	680,226		$	1,494,561	$	(853,556	)	$	641,005

(1)

Weighted average life calculated as of the date of acquisition.

Long-Term Debt (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Long-Term Debt Instrument

Long-term debt at September 30, 2018 and December 31, 2017 consisted of the following:



(in thousands)	September 30, 2018			December 31, 2017
Current portion of long-term debt:
Current portion of 5-year term loan facility expires June 28, 2022	$	30,000		$	20,000
4.500% senior notes, Series E, quarterly interest payments, balloon due September 2018	—			100,000
Total current portion of long-term debt	30,000			120,000
Long-term debt:
Note agreements:
4.200% senior notes, semi-annual interest payments, net of the unamortized discount, balloon due 2024	499,062			498,943
Total notes	499,062			498,943
Credit agreements:
5-year term-loan facility, periodic interest and principal payments, LIBOR plus up to 1.750%, expires June 28, 2022	340,000			365,000
5-year revolving-loan facility, periodic interest payments, LIBOR plus up to 1.500%, plus commitment fees up to 0.250%, expires June 28, 2022	—			—
Total credit agreements	340,000			365,000
Debt issuance costs (contra)	(6,701		)	(7,802		)
Total long-term debt less unamortized discount and debt issuance costs	832,361			856,141
Current portion of long-term debt	30,000			120,000
Total debt	$	862,361		$	976,141

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21521-112644

+ Details

Segment Information (Tables)

9 Months Ended

Sep. 30, 2018

Segment Reporting Information [Line Items]

Segment Information



	Three months ended September 30, 2018
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	261,087	$	143,519	$	78,009	$	48,105	$	130		$	530,850
Investment income	$	1	$	138	$	44	$	51	$	485		$	719
Amortization	$	10,754	$	6,736	$	2,878	$	1,269	$	—		$	21,637
Depreciation	$	1,236	$	1,346	$	385	$	393	$	1,899		$	5,259
Interest expense	$	7,468	$	6,147	$	1,233	$	846	$	(6,731	)	$	8,963
Income before income taxes	$	61,224	$	46,707	$	23,614	$	6,988	$	3,967		$	142,500
Total assets	$	4,651,080	$	2,933,465	$	1,272,795	$	448,027	$	(3,502,561	)	$	5,802,806
Capital expenditures	$	1,467	$	2,420	$	895	$	366	$	4,321		$	9,469



	Three months ended September 30, 2017
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	234,483	$	127,718	$	71,574	$	41,491	$	380		$	475,646
Investment income	$	3	$	124	$	—	$	72	$	292		$	491
Amortization	$	10,540	$	6,913	$	2,845	$	1,137	$	—		$	21,435
Depreciation	$	1,262	$	1,412	$	471	$	402	$	1,942		$	5,489
Interest expense	$	7,216	$	8,304	$	1,515	$	876	$	(8,518	)	$	9,393
Income before income taxes	$	54,950	$	32,203	$	21,219	$	7,910	$	8,137		$	124,419
Total assets	$	4,246,422	$	5,026,918	$	1,258,783	$	432,331	$	(3,550,177	)	$	7,414,277
Capital expenditures	$	844	$	1,357	$	214	$	364	$	1,270		$	4,049



	Nine months ended September 30, 2018
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	772,806	$	374,434	$	219,725	$	138,038	$	495		$	1,505,498
Investment income	$	2	$	384	$	125	$	160	$	1,380		$	2,051
Amortization	$	31,498	$	19,383	$	8,537	$	3,543	$	—		$	62,961
Depreciation	$	3,746	$	4,087	$	1,238	$	1,183	$	6,156		$	16,410
Interest expense	$	21,377	$	20,019	$	4,039	$	2,023	$	(18,772	)	$	28,686
Income before income taxes	$	175,984	$	91,809	$	55,544	$	23,889	$	14,625		$	361,851
Total assets	$	4,651,080	$	2,933,465	$	1,272,795	$	448,027	$	(3,502,561	)	$	5,802,806
Capital expenditures	$	5,828	$	7,313	$	1,762	$	798	$	13,158		$	28,859



	Nine months ended September 30, 2017
(in thousands)	Retail		National Programs		Wholesale Brokerage		Services		Other			Total
Total revenues	$	712,739	$	342,576	$	208,812	$	122,397	$	20,507		$	1,407,031
Investment income	$	6	$	279	$	—	$	224	$	576		$	1,085
Amortization	$	31,704	$	20,664	$	8,621	$	3,412	$	1		$	64,402
Depreciation	$	3,975	$	4,975	$	1,438	$	1,191	$	5,663		$	17,242
Interest expense	$	23,918	$	27,257	$	4,803	$	2,783	$	(29,812	)	$	28,949
Income before income taxes	$	151,783	$	68,127	$	56,569	$	22,480	$	44,429		$	343,388
Total assets	$	4,246,422	$	5,026,918	$	1,258,783	$	432,331	$	(3,550,177	)	$	7,414,277
Capital expenditures	$	3,384	$	3,885	$	1,606	$	856	$	3,166		$	12,897

Investments (Tables)

9 Months Ended

Sep. 30, 2018

Schedule of Held-to-maturity Securities [Line Items]

Schedule of Investments in Fixed Maturity Securities

At December 31, 2017, the Company’s amortized cost and fair values of fixed maturity securities are summarized as follows:



(in thousands)	Cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	29,970	$	—	$	(206	)	$	29,764
Corporate debt	1,072		12		—			1,084
Total	$	31,042	$	12	$	(206	)	$	30,848

At September 30, 2018, the Company’s amortized cost and fair values of fixed maturity securities are summarized as follows:



(in thousands)	Cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	21,722	$	3	$	(462	)	$	21,263
Corporate debt	622		—		(2		)	620
Total	$	22,344	$	3	$	(464	)	$	21,883

Summary of Unrealized Loss Position

December 31, 2017:



	Less than 12 Months					12 Months or More					Total
(in thousands)	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	17,919	$	(157	)	$	11,845	$	(49	)	$	29,764	$	(206	)
Corporate debt	400		—			—		—			400		—
Total	$	18,319	$	(157	)	$	11,845	$	(49	)	$	30,164	$	(206	)

he following table shows the investments’ gross unrealized loss and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2018:



	Less than 12 Months					12 Months or More					Total
(in thousands)	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities	$	8,237	$	(104	)	$	12,727	$	(358	)	$	20,964	$	(462	)
Corporate debt	620		(2		)	—		—			620		(2		)
Total	$	8,857	$	(106	)	$	12,727	$	(358	)	$	21,584	$	(464	)

Amortized Cost and Fair Value of Fixed Maturity Securities by Contractual Maturity

The amortized cost and estimated fair value of the fixed maturity securities at September 30, 2018 by contractual maturity are set forth below:



(in thousands)	Amortized cost		Fair value
Years to maturity:
Due in one year or less	$	4,771	$	4,732
Due after one year through five years	17,341		16,920
Due after five years	232		231
Total	$	22,344	$	21,883

The amortized cost and estimated fair value of the fixed maturity securities at December 31, 2017 by contractual maturity are set forth below:



(in thousands)	Amortized cost		Fair value
Years to maturity:
Due in one year or less	$	16,934	$	16,899
Due after one year through five years	13,876		13,708
Due after five years	232		241
Total	$	31,042	$	30,848

Income Taxes (Tables)	9 Months Ended
Income Taxes (Tables)	Sep. 30, 2018
Income Tax Policy [Abstract]
Income Tax, Policy [Policy Text Block]	NOTE 17· Income Taxes The Tax Cuts and Jobs Act of 2017 (“2017 Tax Reform Act”) made significant changes to the Internal Revenue Code, including, but not limited to, the reduction in the U.S. federal corporate income tax rate from 35.0% to 21.0% for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a participation exemption regime, and a one-time transition tax on the mandatory deemed repatriation of foreign earnings. The Company estimated its provision for income taxes in accordance with the 2017 Tax Reform Act and guidance available upon enactment and as a result recorded $120.9 million as a one-time credit in the fourth quarter of 2017, the period in which the legislation was signed into law. The 2017 estimate includes a provisional benefit of $124.2 million related to the remeasurement of certain deferred tax assets and liabilities, based on the rates at which they are expected to reverse in the future which was partially offset by a provisional amount related to the one-time transition tax on the mandatory deemed repatriation of foreign earnings of $3.3 million based on cumulative foreign earnings of $20.9 million. During the third quarter of 2018, the Company posted a $1.6 million credit to taxes related to the previously calculated amount of $3.3 million for the one-time transition tax on the mandatory deemed repatriation of foreign earnings. The Company has not recorded any additional adjustments to this provisional amount as of September 30, 2018. On December 22, 2017, the SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Reform Act. In accordance with SAB 118, the Company has determined that the deferred tax benefit recorded in connection with the remeasurement of certain deferred tax assets and liabilities and the current tax expense recorded in connection with the transition tax on the mandatory deemed repatriation of foreign earnings was a provisional amount and a reasonable estimate at September 30, 2018 and December 31, 2017. As noted above, the Company posted a $1.6 million credit to income taxes related to the previously calculated amount of $3.3 million for the one-time transition tax on the mandatory deemed repatriation of foreign earnings. Additional work is necessary for a more detailed analysis of the Company’s deferred tax assets and liabilities as well as potential correlative adjustments. Any subsequent adjustment to these amounts will be recorded to current tax expense in the quarter of identification, but no later than one year from the enactment date. The 2017 Tax Reform Act instituted a number of new provisions effective January 1, 2018, including the Global Intangible Low Taxed Income (“GILTI”), Foreign Derived Intangible Income (“FDII”) and Base Erosion and Anti-Abuse Tax (“BEAT”). The Company prepared reasonable estimates of the impact of each of these provisions of the 2017 Tax Reform Act on its effective tax rate for quarter ended September 30, 2018 and determined that the resulting impact was not material. The Company will continue to refine its provisional estimates related to the GILTI, FDII and BEAT rules as additional information is made available.

- Definition

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.

+ References + Details

Basis of Financial Reporting Adopted Guidance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Premiums Commissions And Fees Receivable	$ 736,378		$ 736,378		$ 699,460	$ 546,402
Other Assets, Current	95,799		95,799		100,544	47,864
Insurance Commissions and Fees	529,813	$ 474,609	1,502,219	$ 1,383,899
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			(24,700)
Retained Earnings (Accumulated Deficit)	2,782,504		2,782,504		2,574,114	2,456,599
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						12,107
Premiums Payable To Insurance Companies	732,550		732,550		697,270	685,163
Accounts Payable, Current	84,228		84,228		72,924	64,177
Accrued Liabilities, Current	234,731		234,731		251,542	228,748
Deferred Tax Liabilities, Net, Noncurrent	284,330		284,330		300,760	256,185
Employee Compensation And Benefits	268,045	246,062	790,902	736,445
Other Cost and Expense, Operating	83,697	72,058	243,704	210,289
Income Tax Expense (Benefit)	36,447	48,506	91,048	131,263
Net Income (Loss) Attributable to Parent	106,053	$ 75,913	270,803	$ 212,125
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income			15,791
Accounts Payable [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						8,747
Other Liabilities [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						22,794
Deferred Income Tax Charge [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						44,575
Employee Compensation and Benefits [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			3,396
Operating Expense [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			(6,996)
Income Tax Expense [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			$ 5,309
Retained Earnings [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification					$ 117,500	117,515
Other Current Assets [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						52,680
Premiums Receivable [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						$ 153,058
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Insurance Commissions and Fees	1,477,519
Employee Compensation And Benefits	794,298
Other Cost and Expense, Operating	236,708
Income Tax Expense (Benefit)	85,739
Net Income (Loss) Attributable to Parent	$ 255,012

Basis of Financial Reporting Text Block (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 12,107,000
Insurance Commissions	$ 362,014,000	$ 1,033,589,000
Profit-Sharing Contingent Commission Revenue	(14,327,000)	(39,993,000)
Fees and Commissions, Other	138,664,000	375,918,000
Operating Leases, Future Minimum Payments Due	209,800,000	209,800,000			210,400,000
Share-based Compensation		23,522,000	$ 22,362,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Insurance Commissions		26,600,000
Profit-Sharing Contingent Commission Revenue		6,900,000
Fees and Commissions, Other		(5,000,000.0)
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 117,500,000	$ 117,515,000
Cost to Obtain [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Costs	$ 10,300,000	10,300,000
Capitalized Contract Cost, Amortization		300,000
Cost to Fulfill [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Costs				$ 52,700,000
Capitalized Contract Cost, Amortization		$ 3,600,000

Revenues (Details) - USD ($)	3 Months Ended		9 Months Ended
Revenues (Details) - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Document Period End Date			Sep. 30, 2018
Insurance Commissions	$ 362,014,000		$ 1,033,589,000
Investment Income, Nonoperating	719,000	$ 491,000	2,051,000	$ 1,085,000
Other Income	318,000	546,000	1,228,000	22,047,000
Fees and Commissions, Other	138,664,000		375,918,000
Incentive Commission	11,755,000		44,194,000
Profit-Sharing Contingent Commission Revenue	14,327,000		39,993,000
Guaranteed Supplemental Commission	3,053,000		8,525,000
Revenues	530,850,000	475,646,000	1,505,498,000	1,407,031,000
Contract with Customer, Asset and Liability [Table Text Block]	249,294,000		249,294,000		$ 210,323,000
Contract with Customer, Liability	53,900,000		53,900,000		44,500,000
Contract with Customer, Liability, Noncurrent	9,700,000		9,700,000		6,700,000
Contract with Customer, Liability	63,611,000		63,611,000		$ 51,236,000
Deferred Revenue, Revenue Recognized			8,100,000
Operating Segments [Member]
Segment Reporting Information [Line Items]
Insurance Commissions	(11,000)		(42,000)
Investment Income, Nonoperating	485,000		1,380,000
Other Income	0		9,000
Fees and Commissions, Other	(360,000)		(880,000)
Incentive Commission	16,000		28,000
Profit-Sharing Contingent Commission Revenue	0		0
Guaranteed Supplemental Commission	0		0
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Investment Income, Nonoperating	485,000	292,000	1,380,000	576,000
Revenues	130,000	380,000	495,000	20,507,000
Retail [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Insurance Commissions	207,703,000		609,252,000
Investment Income, Nonoperating	1,000	3,000	2,000	6,000
Other Income	207,000		758,000
Fees and Commissions, Other	33,915,000		94,282,000
Incentive Commission	11,408,000		43,356,000
Profit-Sharing Contingent Commission Revenue	5,280,000		17,879,000
Guaranteed Supplemental Commission	2,573,000		7,277,000
Revenues	261,087,000	234,483,000	772,806,000	712,739,000
National Programs [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Insurance Commissions	92,106,000		249,491,000
Investment Income, Nonoperating	138,000	124,000	384,000	279,000
Other Income	12,000		60,000
Fees and Commissions, Other	43,168,000		106,839,000
Incentive Commission	287,000		295,000
Profit-Sharing Contingent Commission Revenue	7,786,000		17,290,000
Guaranteed Supplemental Commission	22,000		75,000
Revenues	143,519,000	127,718,000	374,434,000	342,576,000
Wholesale Brokerage [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Insurance Commissions	62,216,000		174,888,000
Investment Income, Nonoperating	44,000	0	125,000	0
Other Income	99,000		401,000
Fees and Commissions, Other	13,887,000		37,799,000
Incentive Commission	44,000		515,000
Profit-Sharing Contingent Commission Revenue	1,261,000		4,824,000
Guaranteed Supplemental Commission	458,000		1,173,000
Revenues	78,009,000	71,574,000	219,725,000	208,812,000
Services [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Insurance Commissions	0		0
Investment Income, Nonoperating	51,000	72,000	160,000	224,000
Other Income	0		0
Fees and Commissions, Other	48,054,000		137,878,000
Incentive Commission	0		0
Profit-Sharing Contingent Commission Revenue	0		0
Guaranteed Supplemental Commission	0		0
Revenues	$ 48,105,000	$ 41,491,000	$ 138,038,000	$ 122,397,000

Net Income Per Share - Reconciliation between Basic and Diluted Weighted Average Shares Outstanding (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 106,053	$ 75,913	$ 270,803	$ 212,125
Net income attributable to unvested awarded performance stock	(2,716)	(1,852)	(6,185)	(5,181)
Net income attributable to common shares	$ 103,337	$ 74,061	$ 264,618	$ 206,944
Weighted average number of common shares outstanding - basic (in shares)	278,132	279,512	276,744	280,024
Less unvested awarded performance stock included in weighted average number of common shares outstanding - basic (in shares)	(7,124)	(6,820)	(6,321)	(6,840)
Weighted average number of common shares outstanding for basic earnings per common share (in shares)	271,008	272,692	270,423	273,184
Dilutive effect of stock options (in shares)	4,274	5,094	5,191	4,838
Weighted average number of shares outstanding - diluted (in shares)	275,282	277,786	275,614	278,022
Basic (in dollars per share)	$ 0.38	$ 0.27	$ 0.98	$ 0.76
Diluted (in dollars per share)	$ 0.38	$ 0.27	$ 0.96	$ 0.74

Business Combinations - Additional Information (Detail)	9 Months Ended
Business Combinations - Additional Information (Detail)	Sep. 30, 2018 USD ($) acquisition	Sep. 30, 2017 USD ($) acquisition	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 343,150,000
Number of acquisitions \| acquisition	18	6
Aggregate purchase price of acquisitions	$ 21,400
Payments to Acquire Businesses, Gross	$ 265,890,000
Document Period End Date	Sep. 30, 2018
Goodwill, Acquired During Period	$ 214,559,000
Goodwill assigned	214,559,000
Goodwill currently deductible for income tax purposes	162,900,000
Goodwill related to the recorded earn-out payables	51,700,000
Total revenues related to acquisitions	29,200,000
Income before income taxes related to acquisitions	1,800,000
Estimated acquisition earn-out payables	65,308,000	$ 34,174,000	$ 52,540,000	$ 36,175,000	$ 57,943,000	$ 63,821,000
Maximum Future Contingency payments Acquisitions	151,600,000
Accounts payable
Business Acquisition [Line Items]
Estimated acquisition earn-out payables	$ 14,100,000
Purchased customer accounts
Business Acquisition [Line Items]
Weighted average life (years)	15 years
Non-compete agreements
Business Acquisition [Line Items]
Weighted average life (years)	5 years
Services
Business Acquisition [Line Items]
Goodwill, Acquired During Period	$ 173,025,000
Goodwill assigned	173,000,000.0
National Programs
Business Acquisition [Line Items]
Goodwill, Acquired During Period	18,737,000
Goodwill assigned	18,700,000
Wholesale Brokerage
Business Acquisition [Line Items]
Goodwill, Acquired During Period	5,524,000
Goodwill assigned	5,500,000
Services [Member]
Business Acquisition [Line Items]
Goodwill, Acquired During Period	17,273,000
Goodwill assigned	17,300,000
Other non-current liability
Business Acquisition [Line Items]
Estimated acquisition earn-out payables	$ 51,200,000
Business Combinations - Asset Deals [Member]
Business Acquisition [Line Items]
Number of acquisitions \| acquisition	15
Other Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 33,523,000
Number of acquisitions \| acquisition	1
Goodwill assigned	$ 20,245,000
Business Combinations - Stock Deals [Member]
Business Acquisition [Line Items]
Number of acquisitions \| acquisition	3

Business Combinations - Acquisitions Accounted for Business Combinations (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	$ 11,303
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	13,407
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(22,204)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	343,150
Cash Paid	265,890
Other Payable	3,339
Recorded Earn-Out Payable	51,717
Net Assets Acquired	320,946
Maximum Potential Earn- Out Payable	97,895
Fixed assets	832
Goodwill	214,559
Purchased customer accounts	101,781
Non-compete agreements	506
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	762
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	$ (21,639)
Document Period End Date	Sep. 30, 2018
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	$ (565)
Services [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Goodwill	17,300
Services
Business Combination, Separately Recognized Transactions [Line Items]
Goodwill	173,000
National Programs
Business Combination, Separately Recognized Transactions [Line Items]
Goodwill	18,700
Wholesale Brokerage
Business Combination, Separately Recognized Transactions [Line Items]
Goodwill	5,500
Opus Advisory Group, LLC [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	22,984
Net Assets Acquired	22,984
Fixed assets	11
Goodwill	17,944
Purchased customer accounts	5,008
Non-compete agreements	21
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	0
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Opus Advisory Group, LLC [Member] \| Services
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	20,400
Other Payable	200
Recorded Earn-Out Payable	2,384
Net Assets Acquired	22,984
Maximum Potential Earn- Out Payable	3,600
Kerxton Insurance Agency, Inc. [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(1,414)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	18,161
Net Assets Acquired	16,747
Fixed assets	10
Goodwill	13,417
Purchased customer accounts	4,712
Non-compete agreements	22
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(1,414)
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Kerxton Insurance Agency, Inc. [Member] \| Services
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	13,177
Other Payable	1,490
Recorded Earn-Out Payable	2,080
Net Assets Acquired	16,747
Maximum Potential Earn- Out Payable	2,920
Automotive Development Group, LLC [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	1,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	47,575
Net Assets Acquired	47,575
Fixed assets	67
Goodwill	36,236
Purchased customer accounts	9,751
Non-compete agreements	21
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	0
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Automotive Development Group, LLC [Member] \| Services
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	29,471
Other Payable	559
Recorded Earn-Out Payable	17,545
Net Assets Acquired	47,575
Maximum Potential Earn- Out Payable	20,000
Servco Pacific, Inc. [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	8,189
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	8,075
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(11,307)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	88,774
Net Assets Acquired	77,467
Fixed assets	178
Goodwill	53,901
Purchased customer accounts	16,902
Non-compete agreements	1
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	1,528
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(11,307)
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Servco Pacific, Inc. [Member] \| Services
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	76,551
Other Payable	0
Recorded Earn-Out Payable	916
Net Assets Acquired	77,467
Maximum Potential Earn- Out Payable	7,000
Tower Hill Prime Insurance Company [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	22,928
Net Assets Acquired	22,928
Fixed assets	0
Goodwill	0
Purchased customer accounts	22,928
Non-compete agreements	0
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	0
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Tower Hill Prime Insurance Company [Member] \| National Programs
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	20,300
Other Payable	0
Recorded Earn-Out Payable	2,628
Net Assets Acquired	22,928
Maximum Potential Earn- Out Payable	7,700
Health Special Risk, Inc. [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	3,114
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	818
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(6,272)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	28,395
Net Assets Acquired	22,123
Fixed assets	124
Goodwill	18,737
Purchased customer accounts	5,516
Non-compete agreements	65
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	21
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(5,930)
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	(342)
Health Special Risk, Inc. [Member] \| National Programs
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	20,132
Other Payable	0
Recorded Earn-Out Payable	1,991
Net Assets Acquired	22,123
Maximum Potential Earn- Out Payable	9,000
Professional Disability Associates, LLC [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	1,762
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(1,496)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	26,339
Net Assets Acquired	24,843
Fixed assets	309
Goodwill	17,273
Purchased customer accounts	7,700
Non-compete agreements	82
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	(787)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(1,273)
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	(223)
Professional Disability Associates, LLC [Member] \| Services [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	15,025
Other Payable	0
Recorded Earn-Out Payable	9,818
Net Assets Acquired	24,843
Maximum Potential Earn- Out Payable	17,975
Finance & Insurance Resources, Inc. [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	999
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	54,471
Net Assets Acquired	54,471
Fixed assets	34
Goodwill	36,806
Purchased customer accounts	16,611
Non-compete agreements	21
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	0
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Finance & Insurance Resources, Inc. [Member] \| Services
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	44,940
Other Payable	410
Recorded Earn-Out Payable	9,121
Net Assets Acquired	54,471
Maximum Potential Earn- Out Payable	19,500
Other Acquisitions [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	253
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(1,715)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	33,523
Net Assets Acquired	31,808
Fixed assets	99
Goodwill	20,245
Purchased customer accounts	12,653
Non-compete agreements	273
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(1,715)
Business Acquisition Purchase Price Allocation Other Liabilities Assumed	0
Other Acquisitions [Member] \| Various
Business Combination, Separately Recognized Transactions [Line Items]
Cash Paid	25,894
Other Payable	680
Recorded Earn-Out Payable	5,234
Net Assets Acquired	31,808
Maximum Potential Earn- Out Payable	$ 10,200

Business Combinations - Estimated Fair Values of Aggregate Assets and Liabilities Acquired (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Fair Value Of Assets And Liabilities Statement [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	$ 11,303
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	13,407
Payments to Acquire Businesses, Gross	265,890
Recorded Earn-Out Payable	51,717
Fixed assets	832
Goodwill	214,559
Purchased customer accounts	101,781
Non-compete agreements	506
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	762
Total assets acquired	343,150
Other current liabilities	(21,639)
Total liabilities assumed	(22,204)
Net assets acquired	320,946
Maximum Potential Earn- Out Payable	97,895
Other Acquisitions [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	253
Fixed assets	99
Goodwill	20,245
Purchased customer accounts	12,653
Non-compete agreements	273
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Total assets acquired	33,523
Other current liabilities	(1,715)
Total liabilities assumed	(1,715)
Net assets acquired	31,808
Opus Advisory Group, LLC [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	0
Fixed assets	11
Goodwill	17,944
Purchased customer accounts	5,008
Non-compete agreements	21
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Total assets acquired	22,984
Other current liabilities	0
Total liabilities assumed	0
Net assets acquired	22,984
Kerxton Insurance Agency, Inc. [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	0
Fixed assets	10
Goodwill	13,417
Purchased customer accounts	4,712
Non-compete agreements	22
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Total assets acquired	18,161
Other current liabilities	(1,414)
Total liabilities assumed	(1,414)
Net assets acquired	16,747
Automotive Development Group, LLC [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	1,500
Fixed assets	67
Goodwill	36,236
Purchased customer accounts	9,751
Non-compete agreements	21
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	0
Total assets acquired	47,575
Other current liabilities	0
Total liabilities assumed	0
Net assets acquired	47,575
Servco Pacific, Inc. [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Business Acquisitions Purchase Price Allocation Current Assets Cash And Cash Equivalents	8,189
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	8,075
Fixed assets	178
Goodwill	53,901
Purchased customer accounts	16,902
Non-compete agreements	1
Business Acquisitions Purchase Price Allocation Other Noncurrent Assets	1,528
Total assets acquired	88,774
Other current liabilities	(11,307)
Total liabilities assumed	(11,307)
Net assets acquired	77,467
National Programs [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Goodwill	18,700
Wholesale Brokerage
Fair Value Of Assets And Liabilities Statement [Line Items]
Goodwill	5,500
Services [Member]
Fair Value Of Assets And Liabilities Statement [Line Items]
Goodwill	$ 17,300

Business Combinations - Results of Operations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Document Period End Date			Sep. 30, 2018
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual			$ 29,200
Business Combination Pro Forma Information Income Loss Before Income Taxes Of Acquiree Since Acquisition Date Actual			1,800
Total revenues	$ 533,038	$ 499,846	1,547,556	$ 1,477,640
Income before income taxes	143,402	130,171	372,204	360,034
Net income	$ 106,742	$ 79,422	$ 278,551	$ 222,407
Net income per share:
Basic (in dollars per share)	$ 0.38	$ 0.28	$ 1.01	$ 0.79
Diluted (in dollars per share)	$ 0.38	$ 0.28	$ 0.99	$ 0.78
Weighted Average Basic Shares Outstanding, Pro Forma	271,008	272,692	270,423	273,184
Weighted average number of shares outstanding:
Pro Forma Weighted Average Shares Outstanding, Diluted	275,282	277,786	275,614	278,022

Business Combinations - Additions, Payments, and Net Changes, as well as Interest Expense Accretion on Estimated Acquisition Earn-Out Payables (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Combinations [Abstract]
Document Period End Date			Sep. 30, 2018
Beginning balance		$ 57,943	$ 36,175	$ 63,821
Additions to estimated acquisition earn-out payables	$ 29,646	1,050	51,717	1,332
Payments for estimated acquisition earn-out payables	(16,521)	(23,511)	(25,112)	(39,288)
Subtotal	65,665	35,482	62,780	25,865
Net change in earnings from estimated acquisition earn-out payables:
Change in fair value on estimated acquisition earn-out payables	(928)	(1,784)	945	6,402
Interest expense accretion	571	476	1,583	1,907
Net change in earnings from estimated acquisition earn-out payables	(357)	(1,308)	2,528	8,309
Ending balance	$ 65,308	$ 34,174	$ 65,308	$ 34,174

Goodwill - Changes in Carrying Value of Goodwill by Operating Segment (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Goodwill [Line Items]
Goodwill, Written off Related to Sale of Business Unit	$ 1,004
Goodwill [Roll Forward]
Beginning balance	2,716,079
Goodwill of acquired businesses	214,559
Ending balance	$ 2,929,634
Document Period End Date	Sep. 30, 2018
Services
Goodwill [Line Items]
Goodwill, Written off Related to Sale of Business Unit	$ 0
Goodwill [Roll Forward]
Beginning balance	1,386,248
Goodwill of acquired businesses	173,025
Ending balance	1,559,273
National Programs
Goodwill [Line Items]
Goodwill, Written off Related to Sale of Business Unit	1,004
Goodwill [Roll Forward]
Beginning balance	908,472
Goodwill of acquired businesses	18,737
Ending balance	926,205
Wholesale Brokerage
Goodwill [Line Items]
Goodwill, Written off Related to Sale of Business Unit	0
Goodwill [Roll Forward]
Beginning balance	286,098
Goodwill of acquired businesses	5,524
Ending balance	291,622
Services
Goodwill [Line Items]
Goodwill, Written off Related to Sale of Business Unit	0
Goodwill [Roll Forward]
Beginning balance	135,261
Goodwill of acquired businesses	17,273
Ending balance	$ 152,534

Amortizable Intangible Assets - Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,595,939	$ 1,494,561
Accumulated Amortization	(915,713)	(853,556)
Net Carrying Value	680,226	641,005
Purchased customer accounts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,565,186	1,464,274
Accumulated Amortization	(886,229)	(824,584)
Net Carrying Value	$ 678,957	$ 639,690
Weighted Average Life (Years)	15 years	15 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 30,753	$ 30,287
Accumulated Amortization	(29,484)	(28,972)
Net Carrying Value	$ 1,269	$ 1,315
Weighted Average Life (Years)	6 years 8 months 12 days	6 years 9 months 18 days

Amortizable Intangible Assets - Additional Information (Detail) $ in Millions	Sep. 30, 2018 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense estimated, year one (2015)	$ 84.7
Amortization expense estimated, year two (2016)	83.4
Amortization expense estimated, year three (2017)	76.0
Amortization expense estimated, year four (2018)	72.7
Amortization expense estimated, year five (2019)	$ 68.3

Long-Term Debt - Long-Term Debt Instrument (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Jan. 15, 2015	Sep. 18, 2014
Debt Instrument [Line Items]
Document Period End Date	Sep. 30, 2018
Total current portion of long-term debt	$ 30,000	$ 120,000
Total notes	499,062	498,943
Long-term credit agreements	340,000	365,000
Debt Issuance Costs, Gross	(6,701)	(7,802)
Total long-term debt	832,361	856,141
Current portion of long-term debt	30,000	120,000
Total debt	862,361	976,141
4.500% senior notes, Series E, quarterly interest payments, balloon due September 2018
Debt Instrument [Line Items]
Current portion of senior notes	0	100,000	$ 25,000
4.200% senior notes, semi-annual interest payments, net of the unamortized discount, balloon due 2024
Debt Instrument [Line Items]
Total notes	499,062	498,943
5-year term-loan facility, periodic interest and principal payments, LIBOR plus up to 1.750%, expires June 28, 2022
Debt Instrument [Line Items]
Current portion of loan facility	30,000	20,000
Long-term credit agreements	340,000	365,000
5-year revolving-loan facility, periodic interest payments, LIBOR plus up to 1.500%, plus commitment fees up to 0.250%, expires June 28, 2022
Debt Instrument [Line Items]
Long-term credit agreements	$ 0	$ 0
Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term credit agreements				$ 475,000
Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.15%
Revolving Credit Facility [Member] \| Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.85%

Long-Term Debt - Long-Term Debt Instrument (Additional Information) (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 18, 2014	Sep. 15, 2011
4.500% senior notes, Series E, quarterly interest payments, balloon due 2018
Debt Instrument [Line Items]
Debt instrument maturity year	2018	2018
Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage			4.20%
4.200% senior notes, semi-annual interest payments, net of the unamortized discount, balloon due 2024
Debt Instrument [Line Items]
Debt instrument maturity year	2024	2024
5-year term-loan facility, periodic interest and principal payments, LIBOR plus up to 1.750%, expires June 28, 2022
Debt Instrument [Line Items]
Line of credit facility, expiration period	5 years	5 years
Line of credit facility, expiration date	Jun. 28, 2022	Jun. 28, 2022
Five Year Term Loan Facility Expires In Two Thousand Ninteen Current [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	2022	2022
5-year revolving-loan facility, periodic interest payments, LIBOR plus up to 1.500%, plus commitment fees up to 0.250%, expires June 28, 2022
Debt Instrument [Line Items]
Line of credit facility, expiration period	5 years	5 years
Line of credit facility, expiration date	Jun. 28, 2022	Jun. 28, 2022
Maximum \| Term Loan [Member] \| LIBOR
Debt Instrument [Line Items]
Debt instrument, variable interest rate	1.75%	1.75%
Minimum [Member] \| Term Loan [Member] \| LIBOR
Debt Instrument [Line Items]
Debt instrument, variable interest rate	1.00%
Revolving Credit Facility [Member] \| Maximum
Debt Instrument [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.25%	0.25%
Revolving Credit Facility [Member] \| Maximum \| LIBOR
Debt Instrument [Line Items]
Debt instrument, variable interest rate	1.50%	1.50%
Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.15%
Revolving Credit Facility [Member] \| Minimum [Member] \| LIBOR
Debt Instrument [Line Items]
Debt instrument, variable interest rate	0.85%
Series E [Member] \| Master Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.50%

Long-Term Debt - Narrative (Detail) - USD ($)	3 Months Ended			9 Months Ended	12 Months Ended
Long-Term Debt - Narrative (Detail) - USD ($)	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2017	Mar. 31, 2018	Jun. 28, 2017	Jan. 15, 2015	Sep. 18, 2014	Apr. 17, 2014	Sep. 15, 2011	Feb. 01, 2008	Dec. 22, 2006
Debt Instrument [Line Items]
Document Period End Date				Sep. 30, 2018
Credit facility, outstanding amount		$ 340,000,000		$ 340,000,000	$ 365,000,000
Unsecured revolving credit facility							$ 400,000,000.0			$ 800,000,000.0
Write off of Deferred Debt Issuance Cost		200,000
Debt Issuance Costs, Noncurrent, Net							$ 1,600,000
Debt Instrument, Periodic Payment, Principal		5,000,000.0	$ 5,000,000.0
Proceeds from Issuance of Debt		2,800,000
Unsecured term loans						$ 370,000,000.0
Outstanding debt balance		862,361,000		862,361,000	976,141,000
4.500% senior notes, Series E, quarterly interest payments, balloon due September 2018
Debt Instrument [Line Items]
Current portion of senior notes		0		0	$ 100,000,000			$ 25,000,000.0
Unsecured Senior Notes
Debt Instrument [Line Items]
Debt instrument interest rate stated percentage									4.20%
Debt instrument, face amount									$ 500,000,000.0
Outstanding debt balance		500,000,000.0		$ 500,000,000.0
Term Loan
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal		67,500,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, outstanding amount									$ 475,000,000.0
Master Agreement \| Series C
Debt Instrument [Line Items]
Unsecured senior notes outstanding												$ 25,000,000.0	$ 25,000,000.0
Debt instrument interest rate stated percentage													5.66%
Master Agreement \| Series D
Debt Instrument [Line Items]
Debt instrument interest rate stated percentage												5.37%
Master Agreement \| Series E
Debt Instrument [Line Items]
Unsecured senior notes outstanding											$ 100,000,000.0
Payment for Debt Extinguishment or Debt Prepayment Cost		$ 700,000
Debt instrument interest rate stated percentage											4.50%
LIBOR
Debt Instrument [Line Items]
30-day Adjusted LIBOR Rate		2.125%		2.125%
Maximum \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility fee				0.25%	0.25%
Maximum \| LIBOR \| Term Loan
Debt Instrument [Line Items]
Debt instrument, variable interest rate				1.75%	1.75%
Maximum \| LIBOR \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, variable interest rate				1.50%	1.50%
Scenario, Forecast [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	$ 5,000,000.0

Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities - Significant Non-Cash Investing and Financing Activities (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Document Period End Date	Sep. 30, 2018
Cash and cash equivalents	$ 422,971,000	$ 546,520,000	$ 573,383,000	$ 515,646,000
Restricted Cash and Cash Equivalents	301,716,000	276,687,000	250,705,000	265,637,000
Cash paid during the period for:
Interest	32,896,000	32,504,000
Income taxes	21,380,000	110,853,000
Significant non-cash investing and financing activities
Other payable issued for purchased customer accounts	3,339,000	11,395,000
Estimated acquisition earn-out payables and related charges	51,717,000	1,332,000
Cash and Cash Equivalents inclusive of Restricted Cash [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 724,687,000	$ 823,207,000	$ 824,088,000	$ 781,283,000

Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities Restricted Cash (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 422,971,000	$ 546,520,000	$ 573,383,000	$ 515,646,000
Cash and Cash Equivalents, at Carrying Value	724,687,000	823,207,000	824,088,000	781,283,000
Restricted Cash and Cash Equivalents	301,716,000	276,687,000	250,705,000	265,637,000
Cash and Cash Equivalents inclusive of Restricted Cash [Member]
Cash and cash equivalents	$ 724,687,000	$ 823,207,000	$ 824,088,000	$ 781,283,000

Segment Information - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) Segment	Sep. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment			4
Total revenues	$ 530,850	$ 475,646	$ 1,505,498	$ 1,407,031
Document Period End Date			Sep. 30, 2018
London, Bermuda and Cayman Islands
Segment Reporting Information [Line Items]
Total revenues	$ 3,700	$ 3,900	$ 11,300	$ 11,100

Segment Information - Summarized Financial Information Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 530,850	$ 475,646	$ 1,505,498	$ 1,407,031
Investment income	719	491	2,051	1,085
Amortization	21,637	21,435	62,961	64,402
Depreciation	5,259	5,489	16,410	17,242
Interest expense	8,963	9,393	28,686	28,949
Income before income taxes	142,500	124,419	361,851	343,388
Total assets	5,802,806	7,414,277	5,802,806	7,414,277	$ 5,747,550
Capital expenditures	9,469	4,049	28,859	12,897
Operating Segments
Segment Reporting Information [Line Items]
Investment income	485		1,380
Operating Segments \| Services
Segment Reporting Information [Line Items]
Total revenues	261,087	234,483	772,806	712,739
Investment income	1	3	2	6
Amortization	10,754	10,540	31,498	31,704
Depreciation	1,236	1,262	3,746	3,975
Interest expense	7,468	7,216	21,377	23,918
Income before income taxes	61,224	54,950	175,984	151,783
Total assets	4,651,080	4,246,422	4,651,080	4,246,422
Capital expenditures	1,467	844	5,828	3,384
Operating Segments \| National Programs
Segment Reporting Information [Line Items]
Total revenues	143,519	127,718	374,434	342,576
Investment income	138	124	384	279
Amortization	6,736	6,913	19,383	20,664
Depreciation	1,346	1,412	4,087	4,975
Interest expense	6,147	8,304	20,019	27,257
Income before income taxes	46,707	32,203	91,809	68,127
Total assets	2,933,465	5,026,918	2,933,465	5,026,918
Capital expenditures	2,420	1,357	7,313	3,885
Operating Segments \| Wholesale Brokerage
Segment Reporting Information [Line Items]
Total revenues	78,009	71,574	219,725	208,812
Investment income	44	0	125	0
Amortization	2,878	2,845	8,537	8,621
Depreciation	385	471	1,238	1,438
Interest expense	1,233	1,515	4,039	4,803
Income before income taxes	23,614	21,219	55,544	56,569
Total assets	1,272,795	1,258,783	1,272,795	1,258,783
Capital expenditures	895	214	1,762	1,606
Operating Segments \| Services
Segment Reporting Information [Line Items]
Total revenues	48,105	41,491	138,038	122,397
Investment income	51	72	160	224
Amortization	1,269	1,137	3,543	3,412
Depreciation	393	402	1,183	1,191
Interest expense	846	876	2,023	2,783
Income before income taxes	6,988	7,910	23,889	22,480
Total assets	448,027	432,331	448,027	432,331
Capital expenditures	366	364	798	856
Other
Segment Reporting Information [Line Items]
Total revenues	130	380	495	20,507
Investment income	485	292	1,380	576
Amortization	0	0	0	1
Depreciation	1,899	1,942	6,156	5,663
Interest expense	(6,731)	(8,518)	(18,772)	(29,812)
Income before income taxes	3,967	8,137	14,625	44,429
Total assets	(3,502,561)	(3,550,177)	(3,502,561)	(3,550,177)
Capital expenditures	$ 4,321	$ 1,270	$ 13,158	$ 3,166

Investments - Schedule of Investments in Fixed Maturity Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Single Maturity Date	$ 8,100	$ 8,100
Cost	22,344	31,042
Gross Unrealized Gains	3	12
Gross Unrealized Losses	(464)	(206)
Fair Value	21,883	30,848
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Cost	21,722	29,970
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(462)	(206)
Fair Value	21,263	29,764
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Cost	622	1,072
Gross Unrealized Gains	0	12
Gross Unrealized Losses	(2)	0
Fair Value	$ 620	$ 1,084

Investments - Summary of Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 8,857	$ 18,319
Unrealized Losses, Less than 12 Months	(106)	(157)
Fair Value, 12 Months or More	12,727	11,845
Unrealized Losses, 12 Months or More	(358)	(49)
Fair Value	21,584	30,164
Unrealized Losses	(464)	(206)
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	8,237	17,919
Unrealized Losses, Less than 12 Months	(104)	(157)
Fair Value, 12 Months or More	12,727	11,845
Unrealized Losses, 12 Months or More	(358)	(49)
Fair Value	20,964	29,764
Unrealized Losses	(462)	(206)
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	620	400
Unrealized Losses, Less than 12 Months	(2)	0
Fair Value, 12 Months or More	0	0
Unrealized Losses, 12 Months or More	0	0
Fair Value	620	400
Unrealized Losses	$ (2)	$ 0

Investments - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($) Securities	Dec. 31, 2017 USD ($) Securities
Schedule of Available-for-sale Securities [Line Items]
Document Period End Date	Sep. 30, 2018
Available-for-sale Securities	$ 21,883	$ 30,848
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	$ 4,732	$ 16,899
Number of securities in unrealized loss position \| Securities	23	27
Proceeds from sale of investment in fixed maturity securities	$ 17,000
Proceeds from Sale of Other Investments	$ 17,600
Investment security maturity date, start	Jan. 01, 2018
Investment security maturity date, End	Sep. 30, 2018
Gross realized gains and losses of securities	insignificant
Investments on deposit with the state insurance department	$ 4,000
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	21,263	$ 29,764
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 620	$ 1,084

Investments - Amortized Cost and Fair Value of Fixed Maturity Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost
Due in one year or less	$ 4,771	$ 16,934
Due after one year through five years	17,341	13,876
Due after five years	232	232
Amortized Cost, Total	22,344	31,042
Fair Value
Due in one year or less	4,732	16,899
Due after one year through five years	16,920	13,708
Due after five years	231	241
Fair Value, Total	$ 21,883	$ 30,848

Losses and Loss Adjustment Reserve - Effects of Reinsurance on Premiums Written and Earned (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Written
Direct premiums	$ 469,078
Ceded premiums	(469,065)
Net premiums	13
Earned
Direct premiums	445,140
Ceded premiums	(445,127)
Net premiums	$ 13

Losses and Loss Adjustment Reserve - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018 USD ($) Reinsurer	Dec. 31, 2017 USD ($)
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Ceded rate of premiums under insurance program	100.00%
Document Period End Date	Sep. 30, 2018
Premiums written net	$ 469,065,000
Ceded unpaid loss	98,500,000
Prepaid reinsurance premiums	344,955,000	$ 321,017,000
Reinsurance Recoverable for Paid Claims and Claims Adjustments	40,900
Increase (Decrease) in Loss and Loss Adjustment Expense Reserve	2,100,000
Reserve for losses and loss adjustment expense	$ 98,500,000
Number of reinsurers \| Reinsurer	2
Wright National Flood Insurance Company [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Ceded rate of premiums under insurance program	100.00%
Expenses and allowance rate received in premiums	30.90%
Premiums written net	$ 467,700,000
Wright National Flood Insurance Company [Member] \| Quota Share Agreement
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Effective cedes rate under quota share agreement	100.00%
Commission rate, percent of ceded written premiums	30.50%
Ceded amount	$ 1,400,000
Wright National Flood Insurance Company [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Loss Adjustment Expense	92,519
Case Reserves	161,758
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 485,000

Statutory Financial Information - Additional Information (Detail) - Wright Flood - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Statutory Accounting Practices [Line Items]
Statutory capital and surplus required	$ 7,500,000
Statutory capital and surplus	22,800,000	$ 28,700,000
Statutory net Income	$ 4,300,000	$ 4,800,000

Subsidiary Dividend Restrictions - Additional Information (Detail) - Wright Flood $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Dividend Restrictions [Line Items]
Dividend rate as a percentage of net income	100.00%
Maximum dividend payout that may be made without prior approval	$ 4.8
Maximum
Dividend Restrictions [Line Items]
Dividend rate as a percentage of net income	10.00%

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2018	Mar. 28, 2018	Mar. 14, 2018	Feb. 09, 2018	Nov. 14, 2017
Accelerated Share Repurchases [Line Items]
Shares repurchased, authorized amount		$ 227,500
Shares repurchased, number of shares received initially (in shares)	10,718,319	10,886,546
Fair value of common stock repurchased	$ 386,322	$ 397,572
Common Stock, Shares, Outstanding	276,210,910	279,222,277
Common Stock, Shares Authorized	560,000,000	560,000,000
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10	$ 0.10
Third Accelerated Share Repurchase Agreement [Member]
Accelerated Share Repurchases [Line Items]
Shares repurchased, authorized amount						$ 75,000
Shares repurchased, number of shares received initially (in shares)					168,227	1,290,486
Fair value of common stock repurchased					$ 11,200	$ 63,800
Treasury Stock, Shares, Acquired	1,458,713
Repurchase Agreements [Member]
Accelerated Share Repurchases [Line Items]
Shares repurchased, authorized amount		$ 100,000
2 for 1 Stock Split [Member]
Accelerated Share Repurchases [Line Items]
Common Stock, Shares, Outstanding			276,000,000	138,000,000
Common Stock, Shares Authorized			560,000,000	280,000,000

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Investments, Owned, Federal Income Tax Note [Line Items]
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount	$ 1,600	$ 3,300
Income Tax Expense (Benefit)	$ (36,447)		$ (48,506)	$ (91,048)	$ (131,263)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%		35.00%
Undistributed Earnings of Foreign Subsidiaries		20,900				$ 20,900
Document Period End Date				Sep. 30, 2018
Tax Cuts and Jobs Act 2017 [Member]
Investments, Owned, Federal Income Tax Note [Line Items]
Deferred Tax Liabilities, Deferred Expense		124,200				$ 124,200
Income Tax Expense (Benefit)		$ 120,900

Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Dec. 31, 2018	Sep. 30, 2018
Subsequent Event [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		$ 320,946
Payments to Acquire Businesses, Gross		265,890
Business Acquisition Cost Of Acquired Entity Other Payable		3,339
Business Acquisition Earn Out Payables		$ 97,895
Retail [Member] \| Hays Group [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	$ 705,000
Payments to Acquire Businesses, Gross	$ 605,000
Business Acquisition, Share Price	$ 0.0010
Business Acquisition Cost Of Acquired Entity Other Payable	$ 100,000
Business Acquisition Earn Out Payables	$ 25,000

Legal and Regulatory Proceedings Legal and Regulatory Proceedings (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Loss Contingencies [Line Items]
Litigation Settlement, Amount Awarded from Other Party	$ 20.0

Nature of Operations - Additional Information (Detail)	9 Months Ended
Nature of Operations - Additional Information (Detail)	Sep. 30, 2018 Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	4