Significant Accounting Policies Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net		$ 54,244
Debt and Capital Lease Obligations	$ 1,029,479	913,012
Estimate of Fair Value Measurement [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Long-term Debt, Fair Value	1,035,424	922,123
Reported Value Measurement [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Debt and Capital Lease Obligations	1,029,479	913,012
Fair value, measurements, recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net		54,244
Total assets at fair value	60,664
Non-qualified deferred compensation liabilities		(54,244)
Total liabilities at fair value	(55,400)	(54,670)
Fair value, measurements, recurring | Supplemental Employee Retirement Plans, Defined Benefit
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Non-qualified deferred compensation assets	55,400	54,244
Non-qualified deferred compensation liabilities	(55,400)
Fair value, measurements, recurring | Level 1
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total assets at fair value	55,400
Total liabilities at fair value	(55,400)	(54,244)
Fair value, measurements, recurring | Level 1 | Supplemental Employee Retirement Plans, Defined Benefit
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Non-qualified deferred compensation assets	55,400	54,244
Non-qualified deferred compensation liabilities	(55,400)	(54,244)
Fair value, measurements, recurring | Level 2
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total assets at fair value	5,264
Total liabilities at fair value	0	(426)
Foreign Exchange Contract | Fair value, measurements, recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net	5,264
Foreign Exchange Contract | Fair value, measurements, recurring | Level 2
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net	$ 5,264
Commodity contracts | Fair value, measurements, recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		(426)
Commodity contracts | Fair value, measurements, recurring | Level 2
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		$ (426)