Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 112,851	$ 81,274	$ 248,623	$ 158,970
Other comprehensive income (loss), net of tax:
Changes in net prior service credit and actuarial losses	1,807	2,625	4,555	7,745
Change in fair value of derivatives	681	(159)	(1,670)	(2,647)
Foreign currency translation	22,520	(25,016)	(15,495)	(24,213)
Other comprehensive income (loss)	25,008	(22,550)	(12,610)	(19,115)
Comprehensive income	$ 137,859	$ 58,724	$ 236,013	$ 139,855