Stockholders' Equity and Noncontrolling Interest - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended			1 Months Ended				0 Months Ended
	Sep. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2003 Series A Preferred Stock	Mar. 31, 2013 Series A Cumulative Preferred Stock	Mar. 31, 2008 Series B Preferred Stock	Mar. 31, 2008 Series B Preferred Stock Minimum	Feb. 12, 2013 Series C Cumulative Preferred Stock	Feb. 12, 2013 Series C Cumulative Preferred Stock Minimum	Feb. 12, 2013 Series C Cumulative Preferred Stock Maximum
Class of Stock [Line Items]
Income attributable to noncontrolling interests		$ 4.0	$ 6.4	$ 3.6
Number of depositary shares sold					4,000,000		3,173,115		5,600,000
Depository shares to cumulative redeemable preferred stock ratio					0.01		0.01		0.01
Dividend rate on preferred stock					8.00%		9.00%
Depositary shares, redeemable price (in usd per share)					$ 25.00		$ 25.00
Annual dividend on depositary shares					$ 2.00		$ 2.25		$ 1.71875
Cumulative redeemable preferred stock liquidation preference					$ 25.00		$ 25.00		$ 25.00
Percentage of redeemable preferred stock						60.00%			6.875%
Depository shares redemption date								Mar. 15, 2013		Feb. 12, 2018
Dividends payment date									Apr. 15, 2013
Dividends record date										Feb. 12, 2013	Mar. 31, 2013
Issuance of common stock related to acquisitions	186,968			186,968
Common stock, par value (in usd per share)	$ 0.01	$ 0.01	$ 0.01
Limited partners unit issued (in shares)	1,497,814			1,497,814
Limited partners capital amount	$ 55.8