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, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net earnings	$ 17,927	$ 12,700
Less earnings attributable to RSUs outstanding	(395)	(318)
Net earnings attributable to common stockholders used in basic and diluted earnings per share calculation	$ 17,532	$ 12,382
Basic	43,872	41,383
Incremental shares from stock-based compensation	3	8
Diluted	43,875	41,391
Basic earnings per common share	$ 0.40	$ 0.30
Diluted earnings per common share	$ 0.40	$ 0.30