Deferred Costs (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Components of Deferred Costs Net [Abstract]
Leasing Costs, Total Cost	$ 137,299	$ 123,724
Financing Costs, Total Cost	39,057	37,257
Total Cost	176,356	160,981
Leasing Costs, Accumulated Amortization	(50,321)	(43,930)
Financing Costs, Accumulated Amortization	(12,379)	(10,934)
Total, Accumulated Amortization	(62,700)	(54,864)
Leasing Costs, Deferred Costs, net	86,978	79,794
Financing Costs, Deferred Costs, net	26,678	26,323
Deferred Costs	$ 113,656	$ 106,117