Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Real Estate and Other Assets Held for Sale, Accumulated Depreciation and Amortization	$ 20,690	$ 34,443
Deferred Costs, Leasing, Accumulated Amortization	0	415
General Partner Preferred Units, Issued	1,550	1,550
General Partner Preferred Units, Outstanding	1,550	1,550
General Partner Preferred Units Liquidation Preference	$ 275,000	$ 275,000
General Partner Units, Issued	88,912,253	86,807,402
General Partner Units, Outstanding	88,912,253	86,807,402
Limited Partners' Units, Issued	4,956,376	5,237,367
Limited Partners' Units, Outstanding	4,956,376	5,237,367