Earnings per Common Share - Reconciliation of Numerators and Denominators of Basic and Diluted Earnings Per Common Share Computations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic:
Net (loss) income attributable to common stockholders	$ (10,709)	$ 48,325
Weighted average common shares outstanding	58,062,997	54,519,574
Basic (loss) earnings per common share	$ (0.18)	$ 0.89
Effect of dilutive securities:
Net (loss) income attributable to common stockholders	$ (10,709)	$ 48,325
Adjustment to income for dilutive options and warrants	0	0
Net income (loss), diluted, Total	$ (10,709)	$ 48,325
Weighted average common shares outstanding	58,062,997	54,519,574
Effect of dilutive options and warrants		912,054
Diluted weighted average common shares outstanding	58,062,997	55,431,628
Diluted (loss) earnings per common share	$ (0.18)	$ 0.87