Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 11,269	$ 7,178	$ 22,956	$ 18,126
Other comprehensive income (loss), net of taxes:
Foreign currency translation adjustments, net of taxes	2,339	(13,597)	3,701	(13,306)
Unrealized gain (loss) on cash flow hedging instruments, net of taxes	2,828	(481)	4,500	(3,374)
Unrealized actuarial gain (loss) related to pension liability, net of taxes	35	(46)	20	(129)
Unrealized gain (loss) on postretirement obligation, net of taxes	(5)	(10)	(10)	(20)
Other comprehensive income (loss), net of taxes	5,197	(14,134)	8,211	(16,829)
Comprehensive income (loss)	$ 16,466	$ (6,956)	$ 31,167	$ 1,297