Accumulated Other Comprehensive Income Details 1 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income [Abstract]
Cross Currency Swap interest portion recognized in income	$ (600)
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	277	$ 344
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(3,710)	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(3,433)	344
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(218)	133
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(3,215)	211
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent	4,811	5,039
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent	1,126	1,327
Income Tax Expense (Benefit)	24,135	21,382
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	470	3,923
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	3,685	$ 3,712
Cross Currency Swap Revaluation Portion Recognized in Earnings	$ 3,100