Derivatives (Schedule of Derivative Assets Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ (12)	$ 0
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	551	724
Derivative Assets, Noncurrent	9	0
Derivative Liabilities, Current	(43)	(105)
Fair value of derivative liabilities	(12)	0
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	2,147	2,510
Derivative Liabilities, Current	(212)	(1,205)
Total [Member]
Derivatives, Fair Value [Line Items]
Net Fair value of derivatives	$ 2,440	$ 1,924