Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (331,120)	$ (259,817)	$ (354,998)	$ (266,649)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	152	(2,653)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	19,803	7,525
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3,923	1,960
Other Comprehensive Income (Loss), Net of Tax	23,878	6,832
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(90,973)	(46,480)	(115,322)	(57,394)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	24,349	10,914
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax	24,349	10,914
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1,869)	(1,168)	(2,232)	3,016
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	152	(2,653)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	0	(554)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	211	(977)
Other Comprehensive Income (Loss), Net of Tax	363	(4,184)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(238,278)	(212,169)	$ (237,444)	$ (212,271)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(4,546)	(2,835)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3,712	2,937
Other Comprehensive Income (Loss), Net of Tax	$ (834)	$ 102