Segments - Reconciliation of Total Segment EBITDA to Income Before Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Total Segment EBITDA									$ 148,535	$ 103,985	$ 92,619
Depreciation and amortization									31,502	32,158	32,341
Other income (expense)									1,371	(275)	(1,261)
Income from operations	$ 36,068	$ 26,153	$ 27,831	$ 25,610	$ 28,793	$ 10,338	$ 18,667	$ 14,304	115,662	72,102	61,539
Interest expense, net									(27,125)	(24,549)	(21,800)
Income before income taxes									$ 89,908	$ 47,278	$ 38,478