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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net (loss) income	$ (4,403)	$ 17,537	$ 30,225	$ 53,632
Income attributable to non-controlling interests	(210)	(260)	(505)	(565)
Preferred dividends	(5,133)	(8,383)	(10,266)	(16,766)
Earnings attributable to unvested shares and operating partnership units	0	(175)	(149)	(346)
Net (loss) income attributable to common shareholders after allocation to participating securities	$ (9,746)	$ 8,719	$ 19,305	$ 35,955
Denominators – Number of Shares
Basic—Average shares outstanding	193,170	180,551	193,448	180,548
Assumed conversion of diluted securities	0	658	0	826
Diluted—Average shares outstanding	193,170	181,209	193,448	181,374
(Loss) Earnings Per Share:
Basic	$ (0.05)	$ 0.05	$ 0.10	$ 0.20
Diluted	$ (0.05)	$ 0.05	$ 0.10	$ 0.20