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	$ 24,586	$ 231,011	$ 428,329
Other comprehensive income, net of tax:
Foreign currency translation adjustments	(5,559)	(118,705)	(128,666)
Pension-related adjustments	3,258	1,532	(1,947)
Other comprehensive income	(2,301)	(117,173)	(130,613)
Comprehensive Income	$ 22,285	$ 113,838	$ 297,716