Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2018	Dec. 31, 2021	Jun. 08, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 9,502,000	$ 8,275,000	$ 8,009,000
Tax benefit related to share-based compensation expense	2,600,000	2,200,000	2,200,000
Capitalized share-based compensation expense	$ 0	$ 0	$ 0
Stock option plans remain outstanding		240	139,350		274,630
Number of options, granted	0	0	0
Eligible period of service for participation in plan	2 months
Minimum age for employees to participate in KSOP	21 years
Dividends deducted	$ 400,000
Tax benefit from dividends	$ 100,000
Shares outstanding, employee stock ownership plan	233,270
Percentage of total common shares outstanding	1.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized	929,012
Options issued to non-employee advisors	0
Aggregate intrinsic value of options exercised and sold	$ 100,000	$ 9,400,000	$ 7,900,000
Performance-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	3 years			5 years
Percentage of vesting annually at anniversary				20.00%
Number of RSU's expected to vest	64,000
Performance-based RSUs [Member] | Vesting after three years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting RSUs	100.00%			60.00%
Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSU's expected to vest	117,034
Number of forfeitures expected	0
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period of unrecognized compensation expense	1 year 2 months 12 days
Number of forfeitures expected	1,913	21,649	10,754
Total fair value of RSU's vested based on weighted average grant date values	$ 11,100,000	$ 8,600,000	$ 9,300,000
Stock-based compensation expense for restricted stock	9,500,000	$ 8,300,000	$ 7,900,000
Total unrecognized compensation expense net of forfeitures	$ 10,900,000
Maximum [Member] | Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	14 months
Minimum [Member] | Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	12 months
2016 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction in common stock available for grant	2
2016 Stock Incentive Plan [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option plans remain outstanding	0
Common Stock [Member] | 2016 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock remained available for grants of awards						2,000,000
Common Stock [Member] | 2016 Stock Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award (in years)	7 years
Common Stock [Member] | 2016 Stock Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Rate of exercise price for equity award granted	100.00%