Earnings per Common Share - Computation of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic
Net income (loss)	$ 7,708	$ (3,433)	$ 26,038	$ 6,570
Preferred stock dividends	162	192	490	794
Net income (loss) available to common shareholders	$ 7,546	$ (3,625)	$ 25,548	$ 5,776
Weighted average common shares outstanding for basic earnings per common share	15,577,371	11,627,093	15,604,410	10,775,577
Basic earnings (loss) per common share	$ 0.48	$ (0.31)	$ 1.64	$ 0.54
Diluted
Net income (loss) available to common shareholders—basic	$ 7,546	$ (3,625)	$ 25,548	$ 5,776
Preferred stock dividends	162	192	490	794
Net income (loss) available to common shareholders—diluted	$ 7,708	$ (3,433)	$ 26,038	$ 6,570
Weighted average common shares outstanding for basic earnings per common share	15,577,371	11,627,093	15,604,410	10,775,577
Add: Dilutive effects of convertible preferred shares	1,272,516	1,643,980	1,286,876	2,054,825
Average shares and dilutive potential common shares outstanding—diluted	16,849,887	13,271,073	16,891,286	12,830,402
Diluted earnings (loss) per common share	$ 0.46	$ (0.31)	$ 1.54	$ 0.51