Investment in Real Estate (Details 3) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Long-lived Assets Held for Sale	$ 24,069	$ 31,405
Long-lived Assets Held and Used		102,552
Long-lived Assets Held for Sale Impairment	(1,194)	(3,903)
Long-lived Assets Held and Used Impairment		(1,781)
Long-lived Assets Impairment		(5,684)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Long-lived Assets Held for Sale
Long-lived Assets Held and Used
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Long-lived Assets Held for Sale
Long-lived Assets Held and Used
Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Long-lived Assets Held for Sale	24,069	31,405
Long-lived Assets Held and Used		$ 102,552