Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Income (Loss)
Net income	$ 1,535	$ 14,508	$ 12,050
Derivative instruments
Unrealized losses on derivative instruments	(4,311)	(8,933)	(22,057)
Reclassification adjustment for losses included in termination of derivative instruments	10,143
Reclassification adjustment for losses included in net income	6,427	11,349	18,633
Net gain (loss) recognized in other comprehensive income	12,259	2,416	(3,424)
Tax benefit (expense) related to items of other comprehensive income (loss)	(4,598)	(838)	1,242
Other comprehensive income (loss)	7,661	1,578	(2,182)
Total comprehensive income	$ 9,196	$ 16,086	$ 9,868