Properties, net (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Properties
Operating properties, net	$ 2,772,303	$ 2,802,773
Operating properties
Properties
Less: accumulated depreciation	(553,306)	(503,032)
Operating properties | Land, operating properties
Properties
Gross	486,538	501,210
Operating properties | Buildings and improvements
Properties
Gross	$ 2,839,071	$ 2,804,595