Earnings Per Share - Components of Earnings Per 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
Earnings Per Share [Abstract]
Net income (loss) available to common shareholders	$ 23,451	$ 2,414	$ 40,957	$ 42,989
Weighted-average number of common shares outstanding - basic (shares)	31,223,777	31,671,122	31,142,400	31,554,407
Share-based compensation plans (shares)	420,951	601,622	438,629	750,573
Warrants (shares)	0	4,846	0	7,475
Weighted-average number of common shares - diluted (shares)	31,644,728	32,277,590	31,581,029	32,312,455
Basic earnings per common share (usd per share)	$ 0.75	$ 0.08	$ 1.32	$ 1.36
Diluted earnings per common share (usd per share)	$ 0.74	$ 0.07	$ 1.30	$ 1.33