Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
COMPREHENSIVE INCOME (LOSS):
Net income	$ 306,276	$ 454,433	$ 434,288
Foreign currency translation adjustments, net of tax	18,973	(1,553)	(19,616)
Foreign defined benefit plans, net of tax	(3,719)	(2,324)	0
Total other comprehensive income (loss)	15,254	(3,877)	(19,616)
Total comprehensive income (loss)	$ 321,530	$ 450,556	$ 414,672