Derivative Instruments - Designated as hedging, Financial Position (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Asset Derivatives		$ 1,090
Liability Derivatives	$ (4,890)
Interest Rate Swap [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	90	1,270
Interest Rate Swap [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	(510)	(180)
Interest Rate Swap [Member] | Other long-term liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ (4,470)	$ 0