Earnings Per Share - Computation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 33,649	$ 16,121
Average number of common shares outstanding (in shares)	29,727	30,395
Effect of dilutive stock options and restricted stock (in shares)	178	128
Average number of common shares outstanding used to calculate diluted earnings per share (in shares)	29,905	30,523
Options excluded from diluted earnings per share because of their antidilutive effect (in shares)	0	0