Segment and Related Information - Reconciliation of Operating Income from Segments to Consolidated (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment operating income	$ 131,305	$ 108,043	$ 94,822
Amortization of acquired software	(22,235)	(4,440)	(1,858)
Amortization of customer and trade name intangibles	(36,400)	(10,300)	(6,400)
Other (expense) income, net	(1,998)	381	(355)
Income before income taxes	129,307	108,424	94,467
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment operating income	167,271	118,388	101,226
Amortization of acquired software	(22,235)	(4,440)	(1,858)
Amortization of customer and trade name intangibles	(13,731)	(5,905)	(4,546)
Other (expense) income, net	$ (1,998)	$ 381	$ (355)