Derivative and Hedging Activities Derivative and Hedging Activities - Balance Sheet Location (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Foreign Currency Cash Flow Hedge Asset at Fair Value	$ 0	$ 13
Foreign Currency Cash Flow Hedge Liability at Fair Value	0	281
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	54	100
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value	40	90
Prepaid Expenses and Other Current Assets [Member] | Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivative [Line Items]
Foreign Currency Cash Flow Hedge Asset at Fair Value	0	13
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	54	100
Accrued Liabilities [Member] | Forward Contracts [Member]
Derivative [Line Items]
Derivative Asset, Current	54	113
Derivative Liability, Current	40	371
Accrued Liabilities [Member] | Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivative [Line Items]
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value	40	90
Accrued Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivative [Line Items]
Foreign Currency Cash Flow Hedge Liability at Fair Value	$ 0	$ 281