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
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Line Items]
Net income	$ 8,211	$ 4,138
Basic weighted-average common shares outstanding (in shares)	37,886	36,889
Effect of dilutive stock options (in shares)	150	303
Effect of dilutive restricted stock (in shares)	1,457	1,409
Diluted weighted-average common shares outstanding (in shares)	39,493	38,601
Basic income per common share (in dollars per share)	$ 0.22	$ 0.11
Diluted income per common share (in dollars per share)	$ 0.21	$ 0.11
Stock options | Nonvested restricted stock
Earnings Per Share [Line Items]
Antidilutive securities excluded from diluted income per common share (in shares)	86	387