Earnings Per Share - Reconciliation of Net Income and Number of Common Shares Used in Computations of "Basic" EPS and "Diluted" EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 7,403	$ 23,901	$ 37,628	$ 77,533
Income attributable to non-controlling interests	(116)	(271)	(621)	(836)
Preferred dividends	(5,133)	(8,382)	(15,399)	(25,148)
Earnings attributable to unvested shares and operating partnership units	0	(174)	(149)	(520)
Net income attributable to common shareholders after allocation to participating securities	$ 2,154	$ 15,074	$ 21,459	$ 51,029
Denominators – Number of Shares
Basic—Average shares outstanding	193,203	180,567	193,366	180,555
Assumed conversion of diluted securities	162	940	0	1,064
Diluted—Average shares outstanding	193,365	181,507	193,366	181,619
Earnings Per Share:
Basic	$ 0.01	$ 0.08	$ 0.11	$ 0.28
Diluted	$ 0.01	$ 0.08	$ 0.11	$ 0.28