Distributions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended	12 Months Ended
	Jan. 31, 2020	Jan. 17, 2020	Jan. 15, 2020	Jan. 02, 2020	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Dividends [Line Items]
Common stock issued, discount rate						3.00%
Common stock distributions (in usd per share)						$ 2.12	$ 2.08	$ 2.04
Dividends declared per common share outstanding (in usd per share)					$ 0.53
Distribution to limited partnership unitholders						$ 16,642	$ 15,981	$ 15,268
Dividend Income
Dividends [Line Items]
Common stock distributions (in usd per share)						$ 2.00	$ 1.61	$ 1.70
Return on Invested Capital
Dividends [Line Items]
Return of capital (in usd per share)					$ 0.12	0.12	0.47	0.34
Series C Preferred Stock
Dividends [Line Items]
Preferred stock dividend (in usd per share)						1.80	1.72	$ 1.72
6.125% Series D Preferred Stock, $0.01 Par Value
Dividends [Line Items]
Preferred stock dividend (in usd per share)						1.53	$ 1.05
6.000% Series E Preferred Stock, $0.01 Par Value
Dividends [Line Items]
Preferred stock dividend (in usd per share)						$ 0.06
Subsequent Event
Dividends [Line Items]
Common stock dividend paid		$ 12,300
Distribution to limited partnership unitholders	$ 4,200
Distributions partnership units (in usd per share)	$ 0.53
Preferred stock distributions			$ 2,800
Subsequent Event | 6.125% Series D Preferred Stock, $0.01 Par Value
Dividends [Line Items]
Dividends declared per preferred share outstanding (in usd per share)				$ 0.3828
Subsequent Event | 6.000% Series E Preferred Stock, $0.01 Par Value
Dividends [Line Items]
Dividends declared per preferred share outstanding (in usd per share)				$ 0.3750