Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cumulative Translation Adjustment Summary [Roll Forward]
Beginning Balance	$ (136,020)	$ (36,087)
Other current period change	13,684	(57,372)
Ending Balance	(122,336)	(93,459)
Accumulated Other Comprehensive Income Loss Actuarial Loss Net Of Tax [Roll Forward]
Beginning Balance	(576,993)	(585,941)
Amortization	4,752	4,961
Other current period change	0	0
Ending Balance	(572,241)	(580,980)
Accumulated Other Comprehensive Income Loss Prior Service Credit Net Of Tax [Roll Forward]
Beginning Balance	278	1,758
Amortization	(37)	(351)
Other current period change	0	0
Ending Balance	241	1,407
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(712,735)	(620,270)
Amortization	4,715	4,610
Other current period change	13,684	(57,372)
Ending Balance	$ (694,336)	$ (673,032)