Accumulated Other Comprehensive Loss (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		$ (628,212)	$ (704,542)
Before reclassifications to income		154,456	62,686
Reclassifications to income		11,513	13,644
Net other comprehensive income (loss)		165,969	76,330	$ (534,287)
Ending Balance		(462,243)	(628,212)	(704,542)
Reclassifications before taxes, included in net periodic benefit expense		18,036	14,821
Reclassifications, income tax expense		6,318	5,234
Amount of loss reclassified to interest expense		2,963	2,963	3,000
Reclassifications income tax, included in interest expense		1,037	1,037
Foreign Currency Translation Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(446,555)	(513,004)
Before reclassifications to income		171,725	66,449
Reclassifications to income
Net other comprehensive income (loss)		171,725	66,449
Ending Balance		(274,830)	(446,555)	(513,004)
Retirement and Postretirement Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(171,305)	(179,260)
Before reclassifications to income		(17,269)	(3,763)
Reclassifications to income	[1]	9,587	11,718
Net other comprehensive income (loss)		(7,682)	7,955
Ending Balance		(178,987)	(171,305)	(179,260)
Deferred Loss On Interest Rate Derivative Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(10,352)	(12,278)
Before reclassifications to income
Reclassifications to income	[2]	1,926	1,926
Net other comprehensive income (loss)		1,926	1,926
Ending Balance		$ (8,426)	$ (10,352)	$ (12,278)

[1] Reclassifications before taxes of $14,821 and $18,036 are included in the computation of net periodic benefit expense in 2017 and 2016, respectively. See Note K for additional information. Related income taxes of $5,234 and $6,318 are included in income tax expense in 2017 and 2016, respectively.

[2] Reclassifications before taxes of $2,963 are included in Interest expense in both 2017 and 2016. Related income taxes of $1,037 are included in income tax expense in 2017 and 2016. See Note L for additional information.