Statement of Cash Flows Supplemental Data (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Supplemental Cash Flow Information
Noncash payable and liabilities	$ 12,400,000	$ 16,100,000
Assets acquired at fair value [Abstract]
Investments in real estate		274,840,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill		122,735,000
Liabilities assumed at fair value [Abstract]
Non recourse debt		(222,680,000)
Accounts payable, accrued expenses and other liabilities		(8,912,000)
Prepaid and deferred rental income		(1,791,000)
Net (liabilities assumed) assets acquired excluding cash		$ 164,192,000