Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Available For Sale Securities Gross Unrealized Gain Loss Calculation [Roll Forward]
Tax increment financing bond, beginning balance	$ (1,508)		$ (2,022)		$ (1,898)		$ (2,309)
Unrealized gains/(losses) on tax increment financing bond	(91)		296		299		583
Tax increment financing bond, ending balance	(1,599)		(1,726)		(1,599)		(1,726)
Cash Flow Hedges Derivative Instruments At Fair Value Net Calculation [Roll Forward]
Cash flow hedges, beginning balance	(9,662)		(2,354)		(10,730)		(3,425)
Unrealized gains/(losses) on cash flow hedges	6,319		(7,481)		6,599		(7,087)
Amortization of cash flow hedges	800	[1]	782	[1]	1,588	[1]	1,459	[1]
Cash flow hedges, ending balance	(2,543)		(9,053)		(2,543)		(9,053)
Total accumulated other comprehensive loss	$ (4,142)		$ (10,779)		$ (4,142)		$ (10,779)		$ (12,628)

[1] Amounts reclassified out of AOCL into contractual interest expense.