Significant Accounting Policies Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Debt and Capital Lease Obligations	$ 1,177,741	$ 1,141,910
Estimate of Fair Value Measurement [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Long-term Debt, Fair Value	1,190,603	1,156,181
Reported Value Measurement [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Debt and Capital Lease Obligations	1,177,741	1,141,910
Fair value, measurements, recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net	875	298
Total assets at fair value	50,407	49,628
Total liabilities at fair value	(49,532)	(49,330)
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	49,532	49,330
Non-qualified deferred compensation liabilities	(49,532)	(49,330)
Fair value, measurements, recurring | Level 1
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total assets at fair value	49,532	49,330
Total liabilities at fair value	(49,532)	(49,330)
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	49,532	49,330
Non-qualified deferred compensation liabilities	(49,532)	(49,330)
Fair value, measurements, recurring | Level 2
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net	875	298
Total assets at fair value	875	298
Total liabilities at fair value	$ 0	$ 0