Consolidated Statements of Equity (Unaudited) (Parenthetical) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Dividends paid or accrued on Common Share of Beneficial Interest	$ 0.325	$ 0.325
Dividends paid or accrued on Series D Preferred Share	$ 1.15625
Dividends paid or accrued on Series C Preferred Share		$ 0.8125
Accumulated Distributions in Excess of Net Income
Dividends paid or accrued on Common Share of Beneficial Interest	$ 0.325	$ 0.325
Dividends paid or accrued on Series D Preferred Share	$ 1.15625
Dividends paid or accrued on Series C Preferred Share		$ 0.8125