Long-Term Debt - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Line of credit		$ 147,000,000.0
Line of credit		$ 0	$ 0
Line of credit facility percentage of outstanding common shares		100.00%
Proceeds from Private placement, outstanding balance		$ 29,104,000	29,607,000
Remaining maturity drops period	5 years
Percentage of proceeds from sale of securities imposed as reduction	20.00%
Unamortized debt issuance cost		308,000	$ 385,000
10-year Subordinated Debt [Member]
Debt Instrument [Line Items]
Fixed rate junior subordinated debt securities per security	$ 12,000,000.0	$ 11,700,000
Debt securities final maturity date	Sep. 03, 2031
Interest rate of private placement	3.50%
Subordinated notes description		From and including September 3, 2026 to but excluding September 3, 2031, or up to any early redemption date, the interest rate on the 10-year subordinated notes will reset quarterly to an annual rate equal to the then-current three-month SOFR plus 283 basis points payable quarterly in arrears.
10-year Subordinated Debt [Member] | SOFR Plus [Member]
Debt Instrument [Line Items]
Subordinated notes variable interest rate percentage	2.83%
15-year Subordinated Debt [Member]
Debt Instrument [Line Items]
Fixed rate junior subordinated debt securities per security	$ 8,000,000.0	$ 8,000,000.0
Debt securities final maturity date	Sep. 03, 2036
Interest rate of private placement	4.00%
Subordinated notes description		From and including September 3, 2026 to but excluding September 3, 2031, or up to any early redemption date, the interest rate on the 10-year subordinated notes will reset quarterly to an annual rate equal to the then-current three-month SOFR plus 283 basis points payable quarterly in arrears.
15-year Subordinated Debt [Member] | SOFR Plus [Member]
Debt Instrument [Line Items]
Subordinated notes variable interest rate percentage	2.92%
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Fixed rate junior subordinated debt securities per security					$ 1,000
Minimum investment required under private placement					50,000
Debt securities final maturity date		Sep. 30, 2029
Proceeds from Private placement, outstanding balance		$ 9,700,000			$ 10,000,000
Debt instrument earliest redemption date		Sep. 30, 2024
Interest rate of private placement		5.25%
Remaining maturity drops period		5 years
Percentage of proceeds from sale of securities imposed as reduction		20.00%
TIB [Member]
Debt Instrument [Line Items]
Line of credit				$ 3,000,000.0
Line of credit facility, amount outstanding		$ 0