Calculation of Earnings Per Share - Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.53	$ 0.54	$ 3.48	$ 3.59
Calculation of Basic Earnings Per Share:
Net Income	$ 9,407	$ 9,662	$ 61,884	$ 63,646
Weighted shares outstanding (shares)	17,796,741	17,737,984	17,783,787	17,715,845
Basic Earnings Per Share (in dollars per share)	$ 0.53	$ 0.54	$ 3.48	$ 3.59
Reconciliation of Numerator:
Net Income	$ 9,407	$ 9,662	$ 61,884	$ 63,646
Reconciliation of Denominator:
Weighted shares outstanding - Basic (shares)	17,796,741	17,737,984	17,783,787	17,715,845
Effect of dilutive securities:
Share-based compensation (shares)	61,043	81,389	63,501	81,156
Adjusted denominator-Diluted (shares)	17,857,784	17,819,373	17,847,288	17,797,001
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.53	$ 0.54	$ 3.47	$ 3.58
Diluted Earnings Per Share (in dollars per share)	$ 0.53	$ 0.54	$ 3.47	$ 3.58
Net Income	$ 9,407	$ 9,662	$ 61,884	$ 63,646
Basic (shares)	17,796,741	17,737,984	17,783,787	17,715,845
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.53	$ 0.54	$ 3.48	$ 3.59
Basic (in dollars per share)	$ 0.53	$ 0.54	$ 3.48	$ 3.59
Share-based compensation (shares)	61,043	81,389	63,501	81,156
Diluted (shares)	17,857,784	17,819,373	17,847,288	17,797,001
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.53	$ 0.54	$ 3.47	$ 3.58
Diluted (in dollars per share)	$ 0.53	$ 0.54	$ 3.47	$ 3.58
Retained Earnings [Member]
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 9,407	$ 9,662	$ 61,884	$ 63,646
Calculation of Basic Earnings Per Share:
Net Income	9,407	9,662	61,884	63,646
Reconciliation of Numerator:
Net Income	9,407	9,662	61,884	63,646
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	9,407	9,662	61,884	63,646
Net Income	$ 9,407	$ 9,662	$ 61,884	$ 63,646