Investment in Real Estate (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of net non-cash impairment charges
Total Net Impairment		$ (4,771)	$ 1,246	$ (4,823)
Operating Properties - Held for Sale and Sold Assets [Member]
Summary of net non-cash impairment charges
Total Net Impairment		564	1,411	3,057
Impairment - Discontinued Operations [Member]
Summary of net non-cash impairment charges
Total Net Impairment		564	1,411	3,057
Land Parcels - Held for Sale and Sold Assets [Member]
Summary of net non-cash impairment charges
Total Net Impairment		(5,879)	0	(5,879)
Operating Properties - Held for Use [Member]
Summary of net non-cash impairment charges
Total Net Impairment		544	(165)	(1,406)
Land Parcels - Held for Use [Member]
Summary of net non-cash impairment charges
Total Net Impairment				(595)
Impairment - Continuing Operations [Member]
Summary of net non-cash impairment charges
Total Net Impairment		$ (5,335)	$ (165)	$ (7,880)