Derivatives (Gain Loss of Fair Value Hedge Recognized in Consolidated Statements of Operations) (Details) (Designated as Hedging Instrument, Interest Rate Contracts, Fair Value Hedging, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Designated as Hedging Instrument | Interest Rate Contracts | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate swap	$ 147	$ 1,070	$ 2,536
Related long-term debt	3,635	(777)	(3,266)
Net impact	$ 3,782	$ 293	$ (730)