Earnings per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic Earnings:
Net income (loss) available to common stockholders	$ 106,866	$ 77,896	$ 7,230	$ 127,683	$ (172,215)	$ (64,480)	$ 80,008	$ 41,471	$ 319,675	$ (115,216)	$ 320,527
Effect of dilutive securities:
Income allocated to exchangeable senior notes									0	0	13,340
Income (loss) allocated to non-controlling interest									0		4,450
Dilutive net income (loss) available to stockholders									$ 319,675	$ (115,216)	$ 338,317
Basic Earnings:
Shares available to common stockholders (in shares)									132,305,568	111,637,035	111,610,393
Effect of dilutive securities:
Restricted stock awards (in shares)									12,000	0	20,000
Non-controlling interest OP Units (in shares)											1,425,000
Exchangeable senior notes (in shares)									0	0	9,986,000
Dilutive Shares (in shares)									132,317,853	111,637,035	123,040,827
Earnings (loss) per share:
Basic (in usd per share)	$ 0.75	$ 0.57	$ 0.06	$ 1.05	$ (1.54)	$ (0.58)	$ 0.72	$ 0.37	$ 2.42	$ (1.03)	$ 2.87
Diluted (in usd per share)	$ 0.75	$ 0.57	$ 0.06	$ 1.05	$ (1.54)	$ (0.58)	$ 0.72	$ 0.37	$ 2.42	$ (1.03)	$ 2.75
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Potential common shares excluded from diluted earnings per common share										14,404
Exchangeable Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share
Potential common shares excluded from diluted earnings per common share										1,184,373
Non-controlling interest
Antidilutive Securities Excluded from Computation of Earnings Per Share
Potential common shares excluded from diluted earnings per common share										1,300,068