Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (6,631)	$ (663)	$ 2,589	$ 17,789
Other comprehensive income (loss), net of tax:
Foreign currency translation gain (loss), net of tax	(22,143)	4,313	(21,459)	(10,016)
Change in unrecognized gains (losses) on derivative instruments:
Change in fair value of derivatives	(10,406)	22,018	(1,862)	17,124
Tax (provision) benefit	2,104	(4,495)	342	(3,680)
Change in unrecognized gains (losses) on derivative instruments, net of tax	(8,302)	17,523	(1,520)	13,444
Defined benefit pension plan:
Amortization of actuarial loss	50	147	155	324
Tax provision	(11)	(23)	(33)	(69)
Pension changes, net of tax	39	124	122	255
Other comprehensive income (loss), net of tax	(30,406)	21,960	(22,857)	3,683
Comprehensive income (loss)	$ (37,037)	$ 21,297	$ (20,268)	$ 21,472