Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of reportable business segments | Segment	5
Research and development costs related to software development	$ 19,500	$ 19,300	$ 15,800
Advertising costs	18,200	20,700	20,700
Provision for doubtful accounts	$ 15,564	18,252	13,335
Forgivable loans, forgiveness period, minimum	1 year
Forgivable loans, forgiveness period, maximum	10 years
Unamortized capitalized software cost	$ 17,600	13,400
Amortization of capitalized software cost	6,500	6,700	$ 5,800
Deferred rent	$ 44,900	$ 42,000
Minimum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Definite-lived intangible assets amortization period	1 year
Maximum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Definite-lived intangible assets amortization period	15 years
Lease provisions for renewal options (In years)	5 years
Furniture, Equipment, And Internal-Use Software | Minimum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful of furniture, equipment and internal use software (in years)	3 years
Furniture, Equipment, And Internal-Use Software | Maximum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful of furniture, equipment and internal use software (in years)	7 years
Software and Software Development Costs
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful of furniture, equipment and internal use software (in years)	3 years
Geographic Concentration Risk | Revenues | Non U.S
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue from the work of professionals	28.00%