Calculation of Earnings Per Share - Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.96	$ 0.79	$ 3.05	$ 2.76
Calculation of Basic Earnings Per Share:
Net Income	$ 17,051	$ 13,813	$ 53,985	$ 48,279
Weighted shares outstanding (shares)	17,730,833	17,546,346	17,704,592	17,516,273
Basic Earnings Per Share (in dollars per share)	$ 0.96	$ 0.79	$ 3.05	$ 2.76
Reconciliation of Numerator:
Net Income	$ 17,051	$ 13,813	$ 53,985	$ 48,279
Reconciliation of Denominator:
Weighted shares outstanding - Basic (shares)	17,730,833	17,546,346	17,704,592	17,516,273
Effect of dilutive securities:
Share-based compensation (shares)	79,038	70,150	81,037	68,733
Adjusted denominator-Diluted (shares)	17,809,871	17,616,496	17,785,629	17,585,006
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.96	$ 0.78	$ 3.04	$ 2.75
Diluted Earnings Per Share (in dollars per share)	$ 0.96	$ 0.78	$ 3.04	$ 2.75
Net Income	$ 17,051	$ 13,813	$ 53,985	$ 48,279
Basic (shares)	17,730,833	17,546,346	17,704,592	17,516,273
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.96	$ 0.79	$ 3.05	$ 2.76
Basic (in dollars per share)	$ 0.96	$ 0.79	$ 3.05	$ 2.76
Share-based compensation (shares)	79,038	70,150	81,037	68,733
Diluted (shares)	17,809,871	17,616,496	17,785,629	17,585,006
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.96	$ 0.78	$ 3.04	$ 2.75
Diluted (in dollars per share)	$ 0.96	$ 0.78	$ 3.04	$ 2.75
Retained Earnings [Member]
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 17,051	$ 13,813	$ 53,985	$ 48,279
Calculation of Basic Earnings Per Share:
Net Income	17,051	13,813	53,985	48,279
Reconciliation of Numerator:
Net Income	17,051	13,813	53,985	48,279
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	17,051	13,813	53,985	48,279
Net Income	$ 17,051	$ 13,813	$ 53,985	$ 48,279