Fixed Assets - Major Classifications of Fixed Assets and Related Useful Lives (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 66,235	$ 60,804
Less accumulated depreciation and amortization	(28,759)	(25,474)
Fixed assets, net	37,476	35,330
Land
Property, Plant and Equipment [Line Items]
Fixed assets, gross	5,892	5,892
Building and Improvements
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 25,516	25,304
Building and Improvements | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years
Building and Improvements | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	40 years
Furniture and Equipment
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 11,802	10,881
Furniture and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years
Furniture and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	10 years
Computer Equipment
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 11,393	10,380
Computer Equipment | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	3 years
Computer Equipment | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 11,632	$ 8,347
Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	3 years
Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
Fixed assets, useful life	5 years