Real Estate - Held for Sale (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (Loss) on Disposition of Assets	$ 297	$ 641	$ 37
Number of Disposed Properties Noncontrolling Interests	0	0	0
Number Of Properties Classified As Held For Sale	22	23
Number Of Improved Properties Held for Sale	16	14
Number of Land Parcels Held for Sale	6	9
Inventory, Held-For-Sale, Land	23,807	24,737
Inventory, Held-For-Sale, Building	22,130	21,710
Real Estate Held-for-sale	45,937	46,447
Less impairment	(8,209)	(8,209)
Inventory, Real Estate, Held-for-sale	37,201	37,724
Number Of Disposed Properties Continuing Operations	0	2	2
Number Of Disposed Properties Discontinued Operations	8	16	11
Gain (Loss) on Disposition of Assets, Noncontrolling Interest Portion, Discontinued Operations	(194)	(363)	(14)
Number Of Disposed Properties Continuing and Discontinued Operations	8	18	13
Gain (Loss) on Disposition of Assets, Total, Continuing and Discontinued Operations	527	1,712	2,973
Assets Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Less accumulated depreciation and amortization	527	514
Gain (Loss) on Disposition of Assets	$ 424	$ 1,434	$ 2,950