Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning			$ (39,637)	$ (72,114)
Net current-period other comprehensive income (loss)	$ (2,641)	$ 2,457	10,414	(23,901)
Balance, ending	(17,452)	(61,128)	(17,452)	(61,128)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	(18,780)	(11,502)	(38,413)	14,460
Other comprehensive income (loss) before reclassifications	(3,827)	2,692	15,806	(23,270)
Net current-period other comprehensive income (loss)	(3,827)	2,692	15,806	(23,270)
Balance, ending	(22,607)	(8,810)	(22,607)	(8,810)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	(1,279)	(832)	5,299	(436)
Other comprehensive income (loss) before reclassifications	1,046	(193)	(891)	716
Amounts reclassified from accumulated other comprehensive income	140	(42)	(4,501)	(1,347)
Net current-period other comprehensive income (loss)	1,186	(235)	(5,392)	(631)
Balance, ending	(93)	(1,067)	(93)	(1,067)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	(20,059)	(12,334)	(33,114)	14,024
Other comprehensive income (loss) before reclassifications	(2,781)	2,499	14,915	(22,554)
Amounts reclassified from accumulated other comprehensive income	140	(42)	(4,501)	(1,347)
Net current-period other comprehensive income (loss)	(2,641)	2,457	10,414	(23,901)
Balance, ending	$ (22,700)	$ (9,877)	$ (22,700)	$ (9,877)