Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill deductible for tax purposes	$ 39,032	$ 36,390
Amortization of acquired intangible assets	27,183	28,513	$ 28,543
Intangible assets write-down	11,195	$ 10,714
IT Services
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill impairment	$ 0