Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Currency Translation Adjustments and Other
Beginning balance	$ (136,020)	$ (36,087)	$ 35,875
Other current period change	70,590	99,933	71,962
Ending balance	(206,610)	(136,020)	(36,087)
Net Actuarial Loss
Beginning balance	(576,993)	(585,941)	(477,883)
Amortization	18,876	19,505	14,866
Pension lump sum settlement expense			61,333
Other current period change	(62,175)	(10,557)	(184,257)
Ending balance	(620,292)	(576,993)	(585,941)
Prior Service Credit
Beginning balance	278	1,758	3,760
Amortization	165	(1,411)	(2,676)
Pension lump sum settlement expense			0
Other current period change	(7,573)	(69)	674
Ending balance	(7,130)	278	1,758
Accumulated Other Comprehensive Loss
Beginning balance	(712,735)	(620,270)	(438,248)
Amortization	19,041	18,094	12,190
Pension lump sum settlement expense			61,333
Other current period change	(140,338)	(110,559)	(255,545)
Ending balance	$ (834,032)	$ (712,735)	$ (620,270)