Non-Controlling Interests, Preferred Shares, Common Shares and Common Shares in Treasury - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended				12 Months Ended				1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended		12 Months Ended									1 Months Ended	12 Months Ended
	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 18, 2011	Dec. 31, 2011 Minimum [Member]	Dec. 31, 2010 Minimum [Member]	Dec. 31, 2011 Maximum [Member]	Dec. 31, 2010 Maximum [Member]	Mar. 31, 2011 Stock Purchase Agreement Otto Transaction [Member]	Dec. 31, 2009 Stock Purchase Agreement Otto Transaction [Member]	Aug. 30, 2012 Class J Preferred Shares [Member]	Dec. 31, 2012 Class J Preferred Shares [Member]	Dec. 31, 2011 Class J Preferred Shares [Member]	Dec. 31, 2012 Class H Preferred Shares [Member]	Dec. 31, 2011 Class H Preferred Shares [Member]	Dec. 31, 2012 Class A Preferred Shares [Member]	Dec. 31, 2012 Class B Preferred Shares [Member]	Dec. 31, 2012 Class C Preferred Shares [Member]	Dec. 31, 2012 Class D Preferred Shares [Member]	Dec. 31, 2012 Class E Preferred Shares [Member]	Dec. 31, 2012 Class F Preferred Shares [Member]	Dec. 31, 2012 Class G Preferred Shares [Member]	Aug. 30, 2012 Class I Preferred Shares [Member]	Dec. 31, 2011 Class I Preferred Shares [Member]	Dec. 31, 2012 Class I Preferred Shares [Member]	Dec. 31, 2012 Class K Preferred Shares [Member]	Dec. 31, 2012 Non-Cumulative Preferred Shares [Member]	Dec. 31, 2012 Cumulative Voting Preferred Shares [Member]
Equity [Line Items]
Operating partnership units outstanding		369,176	369,176
Redeemable OP Units outstanding		29,525	29,525
Cumulative redeemable preferred shares		$ 405,000,000	$ 375,000,000									$ 200,000,000	$ 200,000,000	$ 0	$ 205,000,000	$ 205,000,000									$ 170,000,000	$ 0
Preferred stock dividend rate												6.50%	6.50%		7.375%	7.375%								7.50%	7.50%
Cumulative redeemable preferred shares, price per share												$ 500	$ 500		$ 500	$ 500									$ 500
Cumulative redeemable preferred shares share redemption price												$ 25.00												$ 25.00
Cumulative redeemable preferred shares total redemption price per share																								$ 25.1875
Redeemable preferred stock dividend per share prorated to redemption date																								$ 0.1875
Write-off of Preferred Share original issuance costs		5,804,000	6,402,000	0																				5,800,000
Preferred share, stated value													$ 500		$ 500
Cumulative redeemable preferred shares, shares authorized													750,000	750,000	750,000	750,000	750,000	750,000	750,000	750,000	750,000	750,000	750,000		750,000	750,000	750,000	750,000	2,000,000
Common shares, par value		$ 0.10	$ 0.10
Dividend declared per common share		$ 0.48	$ 0.22	$ 0.08
Number of common shares available for purchase											32,900,000
Number of common shares available for purchase through warrants										10,000,000	10,000,000
Amount of gross proceeds expected from stock to be issued and sold per Stock Purchase Agreement											112,500,000
Issuance of warrants, exercise price per share										6.00
Weighted-average purchase price of additional common shares sold										Less than $6.00 per share
Equity derivative liability - affiliate					$ 74,300,000
Dividend yield assumptions						3.00%	2.40%	3.20%	4.20%
Volatility assumptions	36.60%			79.10%