Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Deferred Leasing Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Fully amortized deferred leasing costs and intangibles	$ 9.5
Above-Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Fully amortized deferred leasing costs and intangibles	1.6
In-Place Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Fully amortized deferred leasing costs and intangibles	3.7
Below-Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Fully amortized deferred leasing costs and intangibles	$ 1.0