Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 3,229	$ 3,482	$ 6,518	$ 8,545
Derivative instruments
Unrealized losses on derivative instruments	(755)	(4,831)	(3,053)	(5,171)
Reclassification adjustment for losses included in net income	1,768	2,818	4,215	6,184
Net gain (loss) recognized in other comprehensive income	1,013	(2,013)	1,162	1,013
Tax benefit/(expense) related to items of other comprehensive income	(371)	737	(425)	(371)
Other comprehensive income (loss)	642	(1,276)	737	642
Total comprehensive income	$ 3,871	$ 2,206	$ 7,255	$ 9,187