Consolidated statements of Equity (Unaudited) (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Dividends paid or accrued per Common Share of Beneficial Interest	$ 0.4875	$ 0.4875
Dividends paid or accrued per Series C Preferred Share	$ 1.21875	$ 1.21875
Accumulated Distributions in Excess of Net Income
Dividends paid or accrued per Common Share of Beneficial Interest	$ 0.4875	$ 0.4875
Dividends paid or accrued per Series C Preferred Share	$ 1.21875	$ 1.21875