Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 153,351	$ 172,413	$ 182,391
Other comprehensive income (loss), net of tax:
Changes in net prior service credit and actuarial losses, net of tax (provision) benefit of $(1,786), $(1,960) and $28,408, respectively	1,175	4,972	(50,331)
Change in fair value of derivatives, net of tax (provision) of $(906), $(129) and $(1,934), respectively	1,528	210	2,592
Foreign currency translation, net of tax (provision) of $(2,829), $(9,949) and $(14,027), respectively	(17,753)	(48,364)	(79,766)
Other comprehensive loss	(15,050)	(43,182)	(127,505)
Comprehensive income	$ 138,301	$ 129,231	$ 54,886