Fair Value (Fair Value by Balance Sheet Location) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net derivative asset (liability)	$ (527)	$ (4,335)
Prepaid and other current assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	1,434	245
Other Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	74	0
Derivative Liability - Current
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities, fair value	(1,928)	(4,265)
Other Long-Term Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities, fair value	$ (107)	$ (315)