Federal Funds Purchased and Securities Sold Under Agreements to Repurchase - Schedule of Remaining Contractual Maturity in Repurchase Agreements (Detail) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Assets Sold under Agreements to Repurchase [Line Items]
Federal funds purchased	$ 0	$ 22,573,000
Repurchase agreements, Remaining contractual maturity of the agreements	30,500,000	31,600,000
Total	30,496,000	54,206,000
Overnight & Continuous [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Federal funds purchased		22,573,000
Total	1,528,000	23,688,000
Greater Than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total	28,968,000	30,518,000
US Treasury & Agency Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	30,496,000	31,633,000
US Treasury & Agency Securities [Member] | Overnight & Continuous [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	1,528,000	1,115,000
US Treasury & Agency Securities [Member] | Greater Than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	$ 28,968,000	$ 30,518,000