Consolidated Statements of Stockholders' Equity and Comprehensive Income/(Loss) (Unaudited) (Parenthetical) (USD $)	6 Months Ended
	Jun. 30, 2011
Common distributions declared per share	$ 0.385
6.75% Series G Cumulative Redeemable Preferred Stock
Preferred stock distributions declared	$ 0.843715
6.75% Series G Cumulative Redeemable Preferred Stock | Paid - in Capital
Preferred stock distributions declared	$ 0.843715
6.75% Series G Cumulative Redeemable Preferred Stock | Distributions in Excess of Net Income
Preferred stock distributions declared	$ 0.843715
6.75% Series G Cumulative Redeemable Preferred Stock | Accumulated Other Comprehensive Income/(Loss)
Preferred stock distributions declared	$ 0.843715
6.75% Series G Cumulative Redeemable Preferred Stock | Non-controlling interest
Preferred stock distributions declared	$ 0.843715
Series E Preferred Stock
Preferred stock distributions declared	$ 0.6644
Series E Preferred Stock | Paid - in Capital
Preferred stock distributions declared	$ 0.6644
Series E Preferred Stock | Distributions in Excess of Net Income
Preferred stock distributions declared	$ 0.6644
Series E Preferred Stock | Accumulated Other Comprehensive Income/(Loss)
Preferred stock distributions declared	$ 0.6644
Series E Preferred Stock | Non-controlling interest
Preferred stock distributions declared	$ 0.6644
Paid - in Capital
Common distributions declared per share	$ 0.385
Distributions in Excess of Net Income
Common distributions declared per share	$ 0.385
Accumulated Other Comprehensive Income/(Loss)
Common distributions declared per share	$ 0.385
Non-controlling interest
Common distributions declared per share	$ 0.385