Distributions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	12 Months Ended
	Jan. 31, 2020	Jan. 15, 2020	Jan. 02, 2020	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividends [Line Items]
Common stock issued, discount rate					3.00%
Common stock distributions (in usd per share)					$ 2.12	$ 2.12	$ 2.08
Dividends declared per common share outstanding (in usd per share)				$ 0.53
Common stock dividend paid	$ 12,400
Distribution to limited partnership unitholders	$ 4,200				$ 16,751	$ 16,642	$ 15,981
Distributions partnership units (in usd per share)	$ 0.53
Preferred stock distributions		$ 2,800
Dividend Income
Dividends [Line Items]
Common stock distributions (in usd per share)					$ 1.43	$ 2.00	$ 1.61
Return on Invested Capital
Dividends [Line Items]
Return of capital (in usd per share)				$ 0.69	0.69	0.12	0.47
Series C Preferred Stock
Dividends [Line Items]
Preferred stock dividend (in usd per share)						1.80	1.72
Depositary Shares each representing 1/100th of a share of 6.125% Series D Cumulative Redeemable Preferred Stock, Par Value $0.01 Per Share
Dividends [Line Items]
Preferred stock dividend (in usd per share)					1.53	1.53	$ 1.05
Dividends declared per preferred share outstanding (in usd per share)			$ 0.3828
Depositary Shares each representing 1/100th of a share of 6.000% Series E Cumulative Redeemable Preferred Stock, Par Value $0.01 Per Share
Dividends [Line Items]
Preferred stock dividend (in usd per share)					$ 1.50	$ 0.06
Dividends declared per preferred share outstanding (in usd per share)			$ 0.3750