Consolidated Statements of Equity (Unaudited) (Parenthetical) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Interest rate on exchangeable notes	3.25%		3.25%
Dividends declared, per common share and common unit	$ 0.35	$ 0.70	$ 0.70
Common Stock Additional Paid-in Capital
Interest rate on exchangeable notes	3.25%		3.25%
Common Stock Distributions in Excess of Earnings
Dividends declared, per common share and common unit		$ 0.70	$ 0.70
Total Stockholders' Equity
Interest rate on exchangeable notes	3.25%		3.25%
Dividends declared, per common share and common unit		$ 0.70	$ 0.70
Noncontrolling Interests - Common Units of the Operating Partnership
Dividends declared, per common share and common unit		$ 0.70	$ 0.70