Segment and Related Information - Reconciliation of Operating Income from Segments to Consolidated (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment operating income	$ 118,388	$ 101,226	$ 73,723
Amortization of acquired software	(4,440)	(1,858)	(2,078)
Amortization of customer and trade name intangibles	(10,300)	(6,400)	(6,800)
Other income (expense), net	381	(355)	(1,309)
Income before income taxes	108,424	94,467	65,819
Segment Reconciling Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Amortization of acquired software	(4,440)	(1,858)	(2,078)
Amortization of customer and trade name intangibles	(5,905)	(4,546)	(4,517)
Other income (expense), net	$ 381	$ (355)	$ (1,309)