Significant Accounting Policies Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Debt and Capital Lease Obligations	$ 919,984	$ 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	931,601	1,156,181
Reported Value Measurement [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Debt and Capital Lease Obligations	919,984	1,141,910
Fair value, measurements, recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net		298
Total assets at fair value	51,959	49,628
Total liabilities at fair value	(53,644)	(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	51,959	49,330
Non-qualified deferred compensation liabilities	(51,959)	(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	51,959	49,330
Total liabilities at fair value	(51,959)	(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	51,959	49,330
Non-qualified deferred compensation liabilities	(51,959)	(49,330)
Fair value, measurements, recurring \| Level 2
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net		298
Total assets at fair value	0	298
Total liabilities at fair value	(1,685)	$ 0
Foreign Exchange Contract \| Fair value, measurements, recurring
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Foreign exchange contracts, net	(1,685)
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	$ (1,685)

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value portion of asset contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward contracts, and swaps.

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Aggregation of the liabilities reported on the balance sheet measured at fair value on a recurring basis by the entity.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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