Federal Funds Purchased and Securities Sold Under Agreement to Repurchase - Schedule of Remaining Contractual Maturity in Repurchase Agreements and Collateral Pledged (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Assets Sold under Agreements to Repurchase [Line Items]
Federal funds purchased	$ 0	$ 22,600,000
Repurchase agreements, Remaining contractual maturity of the agreements	28,200,000
Total	28,218,000	$ 54,206,000
US Treasury & Agency Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	28,218,000
Greater Than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total	28,218,000
Greater Than 90 Days [Member] | US Treasury & Agency Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	$ 28,218,000