Condensed Consolidating Statements of Comprehensive (Loss) Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Statement Of Income Captions [Line Items]
Net (loss) income	$ (52,165)	$ 11,228	$ (22,310)	$ 30,157
Foreign currency translation adjustment	(2,696)	7,566	(7,053)	19,165
Comprehensive (loss) income	(54,861)	18,794	(29,363)	49,322
Eliminations
Condensed Statement Of Income Captions [Line Items]
Net (loss) income			(8,983)
Comprehensive (loss) income			(8,983)
Guarantors
Condensed Statement Of Income Captions [Line Items]
Net (loss) income	(48,904)	6,093	(17,692)	16,845
Comprehensive (loss) income	(48,904)	6,093	(17,692)	16,845
Non-Guarantors
Condensed Statement Of Income Captions [Line Items]
Net (loss) income	(3,261)	5,135	4,365	13,312
Foreign currency translation adjustment	(2,696)	7,566	(7,053)	19,165
Comprehensive (loss) income	$ (5,957)	$ 12,701	$ (2,688)	$ 32,477