Stockholders' Equity and Noncontrolling Interest - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		1 Months Ended			0 Months Ended		0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	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	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	$ 4,433,000	$ 1,168,000	$ 6,857,000	$ (418,000)
Percentage of redeemable preferred stock					60.00%			6.875%
Dividend rate on preferred stock					8.00%	9.00%	8.00%
Outstanding depositary shares							1.6
Depository shares to cumulative redeemable preferred stock ratio							0.01	0.01
Cumulative redeemable preferred stock liquidation preference							$ 25.00		$ 25.00
Annual dividend on depositary shares							$ 2.00	$ 1.71875
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