Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Accumulated depreciation				$ 94,093	$ 96,700
Proceeds from sale of property and equipment				$ 3,209	814	$ 5,059
Asset Held for Sale [Member] | Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of property and equipment	$ 1,300	$ 1,200	$ 400
Asset Held for Sale [Member] | Computer Equipment [Member] | Other Income (Expense), Net [Member]
Property, Plant and Equipment [Line Items]
Gain (Loss) on fair value of assets less costs to sell		(300)
Other Current Assets [Member] | Asset Held for Sale [Member] | Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross					83,900
Accumulated depreciation					80,700
Fair value of assets less costs to sell		$ 2,900			$ 3,200