CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Common shares, par value	$ 0.10	$ 0.10
Common shares, shares authorized	500,000,000	500,000,000
Common shares, shares issued	309,738,002	277,114,784
Treasury at cost	717,614	833,934
Class H Preferred Stock
Cumulative redeemable preferred shares, liquidation value	$ 500	$ 500
Cumulative redeemable preferred shares, shares authorized	750,000	750,000
Cumulative redeemable preferred shares, shares issued	410,000	410,000
Cumulative redeemable preferred shares, shares outstanding	410,000	410,000
Preferred stock dividend rate	7.375%	7.375%
Cumulative redeemable preferred shares, par value
Class I Preferred Stock
Cumulative redeemable preferred shares, liquidation value	$ 0	$ 500
Cumulative redeemable preferred shares, shares authorized	0	750,000
Cumulative redeemable preferred shares, shares issued	0	340,000
Cumulative redeemable preferred shares, shares outstanding	0	340,000
Preferred stock dividend rate	0.00%	7.50%
Cumulative redeemable preferred shares, par value
Class J Preferred Stock
Cumulative redeemable preferred shares, liquidation value	$ 500	$ 0
Cumulative redeemable preferred shares, shares authorized	750,000	0
Cumulative redeemable preferred shares, shares issued	400,000	0
Cumulative redeemable preferred shares, shares outstanding	400,000	0
Preferred stock dividend rate	6.50%	0.00%
Cumulative redeemable preferred shares, par value