Stockholders' Equity and Noncontrolling Interest - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	6 Months Ended		3 Months Ended			1 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013 Series A Cumulative Redeemable Preferred Stock	Mar. 31, 2013 9% Series B Cumulative Redeemable Preferred Stock	Mar. 31, 2013 Series A Preferred Stock	Feb. 12, 2013 6.875 Series C Cumulative Redeemable Preferred Stock	Feb. 12, 2013 6.875 Series C Cumulative Redeemable Preferred Stock Minimum	Feb. 12, 2013 6.875 Series C Cumulative Redeemable Preferred Stock Maximum
Class of Stock [Line Items]
Income (loss) attributable to noncontrolling interests	$ (418,000.0)	$ 3,000,000.0
Percentage of redeemable preferred stock			60.00%
Dividend rate on preferred stock			8.00%	9.00%	8.00%	6.875%
Outstanding depositary shares					1.6
Depository shares to cumulative redeemable preferred stock ratio					0.01	0.01
Depositary shares, redeemable price per share					$ 25.00
Annual dividend on depositary shares					$ 2.00	$ 1.71875
Cumulative redeemable preferred stock liquidation preference					$ 25.00	$ 25.00
Number of depositary shares sold						5.6
Cash proceeds from sale depositary shares						$ 135,200,000
Dividend payment accrual date							Feb. 12, 2018
Dividend payment date						Apr. 15, 2013
Dividends record date							Feb. 12, 2013	Mar. 31, 2013