Deferred Costs (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Components of Deferred Costs Net [Abstract]
Leasing Costs, Total Cost	$ 145,212	$ 140,772
Financing Costs, Total Cost	40,828	38,929
Total Cost	186,040	179,701
Leasing Costs, Accumulated Amortization	(56,536)	(50,990)
Financing Costs, Accumulated Amortization	(10,322)	(13,349)
Total, Accumulated Amortization	(66,858)	(64,339)
Leasing Costs, Deferred Costs, net	88,676	89,782
Financing Costs, Deferred Costs, net	30,506	25,580
Deferred Costs	$ 119,182	$ 115,362