Net Income Per Common Share - Summary of Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Line Items]
Net income	$ 8,526	$ 4,220	$ 26,259	$ 21,893
Basic weighted-average common shares outstanding (in shares)	37,393	31,221	37,174	30,658
Effect of dilutive stock options (in shares)	318	1,084	371	391
Effect of dilutive restricted stock awards (in shares)	1,410	97	1,426	0
Diluted weighted-average common shares outstanding (in shares)	39,121	32,402	38,971	31,049
Basic income per common share outstanding (in dollars per share)	$ 0.23	$ 0.14	$ 0.71	$ 0.71
Diluted income per common share outstanding (in dollars per share)	$ 0.22	$ 0.13	$ 0.67	$ 0.71
Stock options | Nonvested restricted stock
Earnings Per Share [Line Items]
Antidilutive securities excluded from diluted income per common share (in shares)	322	448	378	1,873