XML 52 R40.htm IDEA: XBRL DOCUMENT v3.7.0.1
Business Combinations - Additional Information (Detail)
 3 Months Ended 183 Months Ended
Mar. 31, 2017
USD ($)
Entity
Mar. 31, 2016
USD ($)
Entity
Mar. 31, 2017
USD ($)
Entity
Business Acquisition [Line Items]      
Accretion of the discount on acquisition $ 5,100,000 $ 4,200,000  
Number of companies acquired | Entity 40 32 432
Aggregate amount of maximum earnout obligations related to acquisitions $ 565,300,000    
Aggregate amount of maximum earnout obligations related to acquisitions, recorded in consolidated balance sheet 268,300,000    
Income (expense) related to net adjustments to estimated fair value of liability for earnout obligations (6,700,000) $ 300,000  
Goodwill 91,900,000   $ 91,900,000
Expiration lists 105,100,000   105,100,000
Non-compete agreements 1,000,000   1,000,000
Total revenues related to acquisitions in the aggregate 1,414,400,000 $ 1,317,200,000  
Brokerage and Risk Management [Member]      
Business Acquisition [Line Items]      
Goodwill 91,900,000   91,900,000
Expiration lists 105,100,000   105,100,000
Non-compete agreements $ 1,000,000   1,000,000
Expiration Lists [Member] | Minimum [Member]      
Business Acquisition [Line Items]      
Estimated useful lives of intangibles assets, years 3 years    
Expiration Lists [Member] | Maximum [Member]      
Business Acquisition [Line Items]      
Estimated useful lives of intangibles assets, years 15 years    
Non-Compete Agreements [Member] | Minimum [Member]      
Business Acquisition [Line Items]      
Estimated useful lives of intangibles assets, years 3 years    
Non-Compete Agreements [Member] | Maximum [Member]      
Business Acquisition [Line Items]      
Estimated useful lives of intangibles assets, years 5 years    
Trade Names [Member] | Minimum [Member]      
Business Acquisition [Line Items]      
Estimated useful lives of intangibles assets, years 3 years    
Trade Names [Member] | Maximum [Member]      
Business Acquisition [Line Items]      
Estimated useful lives of intangibles assets, years 5 years    
2017 Acquisitions [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]      
Business Acquisition [Line Items]      
Revenue growth rate 5.00%    
Discount rate 8.50%    
2017 Acquisitions [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]      
Business Acquisition [Line Items]      
Revenue growth rate 15.00%    
Discount rate 9.00%    
2016 Acquisitions [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]      
Business Acquisition [Line Items]      
Revenue growth rate 3.00%    
Discount rate 12.00%    
Attrition rate 3.30%    
2016 Acquisitions [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]      
Business Acquisition [Line Items]      
Revenue growth rate 5.50%    
Discount rate 12.20%    
Attrition rate 7.30%    
Business Acquisition [Member]      
Business Acquisition [Line Items]      
Annualized revenue of business acquisitions $ 62,500,000    
Total revenues related to acquisitions in the aggregate 14,800,000    
Net earnings 500,000    
Business Acquisition [Member] | Brokerage [Member]      
Business Acquisition [Line Items]      
Expiration lists 105,100,000   105,100,000
Non-compete agreements 1,000,000   1,000,000
Deferred tax liability 5,400,000   5,400,000
Goodwill related to nondeductible amortizable intangible assets 5,400,000    
Business Acquisition [Member] | Expiration Lists [Member] | Brokerage [Member]      
Business Acquisition [Line Items]      
Business acquisition not deductible for income tax purposes 16,100,000   16,100,000
Business Acquisition [Member] | Non-Compete Agreements [Member] | Brokerage [Member]      
Business Acquisition [Line Items]      
Business acquisition not deductible for income tax purposes $ 100,000   $ 100,000