CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common dividends, per share (in dollars per share)			$ 0.60
Series C preferred dividends and dividends payable, per share	$ 1.572	$ 1.572	$ 1.572
Series A Cumulative Redeemable Preferred Stock
Preferred dividends and dividends payable, per share	$ 2.00	$ 2.00	$ 2.00
Series D Cumulative Redeemable Preferred Stock
Preferred dividends and dividends payable, per share	$ 1.472222