Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Available For Sale Securities Gross Unrealized Gain Loss Calculation [Roll Forward]
Tax increment financing bond, beginning balance	$ (2,309)	$ (2,543)
Unrealized gain/(loss) on tax increment financing bond	287	(135)
Tax increment financing bond, ending balance	(2,022)	(2,678)
Cash Flow Hedges Derivative Instruments At Fair Value Net Calculation [Roll Forward]
Cash flow hedges, beginning balance	(3,425)	(1,105)
Unrealized gains on cash flow hedges	1,104	0
Amortization of settled cash flow hedges	(33)	(29)
Cash flow hedges, ending balance	(2,354)	(1,134)
Total accumulated other comprehensive loss	$ (4,376)	$ (3,812)	$ (5,734)