Acquisitions - Allocated Aggregate Purchase Price of Acquisitions (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 416,139	$ 384,697
Centric Insurance Agency (Centric), Clearview National Partners, LLC (Clearview) and Lewis Birch & Richardo, LLC (LBR) [Member]
Business Acquisition [Line Items]
Cash	382
Accounts receivable	3,408
Work in process	900
Other assets	406
Identifiable intangible assets	11,109
Current liabilities	(3,690)
Total identifiable net assets	12,515
Goodwill	31,925
Aggregate purchase price	$ 44,440

Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Work In Progress

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- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount of liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

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- Definition

Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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