Federal Funds Purchased and Securities Sold Under Agreements to Repurchase - Schedule of Remaining Contractual Maturity in Repurchase Agreements (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	$ 31,700	$ 29,300
Total	31,680	29,268
Overnight & Continuous [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total	1,009	1,062
30-90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total	20,806	3,900
Greater Than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total	9,865	24,306
US Treasury & Agency Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	31,680	29,268
US Treasury & Agency Securities [Member] | Overnight & Continuous [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	1,009	1,062
US Treasury & Agency Securities [Member] | 30-90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements, Remaining contractual maturity of the agreements	20,806	3,900
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	$ 9,865	$ 24,306