Derivative Financial Instruments Activity of Hedging Instruments in Accumulated OCI (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Accumulated Net Gain (Loss) from Derivative and Nonderivative Instruments Designated as Hedging Instruments [Member]	Dec. 31, 2013 Accumulated Net Gain (Loss) from Derivative and Nonderivative Instruments Designated as Hedging Instruments [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Derivative and Nonderivative Instruments Designated as Hedging Instruments [Member]	Dec. 31, 2012 Accumulated Net Gain (Loss) from Derivative and Nonderivative Instruments Designated as Hedging Instruments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	$ (21,722)		$ (15,473)	$ (15,636)	$ (16,142)	$ (16,069)
Unrealized gain (loss) on derivative instruments	(95)	(73)
Realized losses reclassified into net income (loss)	258	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	$ (24,836)		$ (15,473)	$ (15,636)	$ (16,142)	$ (16,069)