Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 193,814	$ 223,994	$ 269,659
Other comprehensive income (loss), net of tax:
Changes in net prior service credit and net actuarial losses, net of tax (provision) benefit of $(2,540), $16,248 and $3,017, respectively	15,364	(49,644)	(6,293)
Change in fair value of derivatives, net of tax benefit of $683, $283 and $355, respectively	(2,174)	(919)	(613)
Foreign currency translation, net of tax (provision) benefit of $(1,559), $(3,914) and $17,131, respectively	(4,124)	(29,272)	63,874
Other comprehensive income (loss)	9,066	(79,835)	56,968
Comprehensive income	$ 202,880	$ 144,159	$ 326,627