Derivative Instruments (Details 1) (Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset (short-term)	$ 1,999
Derivative asset (long-term)	388	830
Derivative liability (short-term)	$ (129)