Derivative Instruments and Hedging Activities Additional Information (Details) (Foreign Exchange Contract [Member], Cash Flow Hedging [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Foreign Exchange Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 566	$ 1,107