Earnings Per Common Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net earnings	$ 12,700	$ 10,927
Less earnings attributable to RSUs outstanding	(318)	(246)
Net earnings attributable to common stockholders used in basic and diluted earnings per share calculation	$ 12,382	$ 10,681
Basic	41,383	40,873
Incremental shares from stock-based compensation	8	18
Diluted	41,391	40,891
Basic earnings per common share	$ 0.30	$ 0.26
Diluted earnings per common share	$ 0.30	$ 0.26