CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest [Abstract]
Net income	$ 40,553	$ 20,400
Unrealized gain on defined benefit plan, net of tax	1,894	9,719
Unrealized gain (loss) on swaps and collars, net of tax	3,826	(1,438)
Unrealized foreign currency loss, net of tax	(3,738)	(9,614)
Comprehensive income	42,535	19,067
Less: Comprehensive income attributable to noncontrolling interest	(1,101)	(232)
Total comprehensive income attributable to common stockholders	$ 41,434	$ 18,835