Earnings Per Share - Computation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net income	$ 16,121	$ 22,726
Average number of common shares outstanding (in shares)	30,395	30,424
Effect of dilutive stock options and restricted stock (in shares)	128	234
Average number of common shares outstanding used to calculate diluted earnings per share (in shares)	30,523	30,658
Options excluded from diluted earnings per share because the effect of these options was antidilutive (in shares)	0	0