CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest [Abstract]
Net income	$ 99,229	$ 154,115	$ 105,406
Unrealized (loss) gain on defined benefit plan, net of tax	(3,723)	(4,142)	3,440
Unrealized (loss) gain on hedge instruments, net of tax	(3,183)	(3,652)	737
Unrealized foreign currency gain (loss), net of tax	41,439	1,501	(22,543)
Comprehensive income	133,762	147,822	87,040
Less: Comprehensive income attributable to noncontrolling interest	(1,141)	(865)	(1,385)
Total comprehensive income attributable to common stockholders	$ 132,621	$ 146,957	$ 85,655