Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Components of Income Tax Benefit Provision
Tax provision (Benefit) associated with income from operations on sold properties which is included in discontinued operations	$ (119)		$ (384)
Tax Provision (Benefit) Associated with Gains and Losses on Sale of Real Estate which is Included in Discontinued Operations	(1,127)		(1,462)
Tax provision (Benefit) associated with gains and losses on the sale of real estate	(452)	(342)	(143)
Income Tax (Provision) Benefit	(450)	(2,963)	25,185
Income tax benefit (provision)	$ (2,148)	$ (3,305)	$ 23,196