Earnings Per Share - Reconciliation of Net Income (Loss) 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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ 17,537	$ (2,633)	$ 53,632	$ (56,530)
Plus: Income attributable to non-controlling interests	(260)	(696)	(565)	(952)
Less: Preferred dividends	(8,383)	(8,383)	(16,766)	(16,766)
Less: Earnings attributable to unvested shares and operating partnership units	(175)	(650)	(346)	(852)
Net income (loss) attributable to common shareholders after allocation to participating securities	$ 8,719	$ (12,362)	$ 35,955	$ (75,100)
Denominators – Number of Shares
Basic—Average shares outstanding	180,551	184,634	180,548	184,595
Assumed conversion of diluted securities	658	0	826	0
Diluted—Average shares outstanding	181,209	184,634	181,374	184,595
Earnings (Loss) Per Share:
Basic	$ 0.05	$ (0.07)	$ 0.20	$ (0.41)
Diluted	$ 0.05	$ (0.07)	$ 0.20	$ (0.41)