Derivative and Hedging Activities Derivative and Hedging Activities - Notional Values (Details) (Foreign Exchange Forward [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Designated as Hedging Instrument [Member] | Long [Member]
Derivatives, Fair Value [Line Items]
Purchase	$ 16,903	$ 0
Not Designated as Hedging Instrument [Member] | Long [Member]
Derivatives, Fair Value [Line Items]
Purchase	1,043	15,039
Not Designated as Hedging Instrument [Member] | Short [Member]
Derivatives, Fair Value [Line Items]
Sell	$ 4,925	$ 20,945