Loans and Allowance for Credit Losses - Troubled Debt Restructurings Identified During Period (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Contract	Dec. 31, 2021 USD ($) Contract	Dec. 31, 2020 USD ($) Contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	5	30	41
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 693	$ 9,370	$ 14,874
Financing Receivable, Troubled Debt Restructuring	676	1,690	13,969
Financing Receivable Troubled Debt Restructuring Specific Reserve	0	0	636
Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	683	8,901	14,098
Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	10	469	776
Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0	$ 0	$ 0
Commercial Loan [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		6	4
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 7,893	$ 2,805
Financing Receivable, Troubled Debt Restructuring		288	2,196
Financing Receivable Troubled Debt Restructuring Specific Reserve		$ 0	$ 636
Commercial Loan [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		6	4
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 7,893	$ 2,805
Financing Receivable, Troubled Debt Restructuring		288	2,196
Financing Receivable Troubled Debt Restructuring Specific Reserve		0	636
Commercial Loan [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		7,893	2,176
Commercial Loan [Member] | Contractual Payment Modification [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		7,893	2,176
Commercial Loan [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	629
Commercial Loan [Member] | Contractual Interest Rate Reduction [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	629
Commercial Loan [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	0
Commercial Loan [Member] | Extended Maturity [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 0	$ 0
Residential Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	5	15	18
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 693	$ 660	$ 950
Financing Receivable, Troubled Debt Restructuring	676	624	791
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 0	$ 0	$ 0
Residential Real Estate [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	5	12	9
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 693	$ 530	$ 546
Financing Receivable, Troubled Debt Restructuring	676	502	411
Financing Receivable Troubled Debt Restructuring Specific Reserve	0	$ 0	$ 0
Residential Real Estate [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		3	9
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 130	$ 404
Financing Receivable, Troubled Debt Restructuring		122	380
Financing Receivable Troubled Debt Restructuring Specific Reserve		0	0
Residential Real Estate [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	683	301	917
Residential Real Estate [Member] | Contractual Payment Modification [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	683	171	513
Residential Real Estate [Member] | Contractual Payment Modification [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		130	404
Residential Real Estate [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	10	359	33
Residential Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	10	359	33
Residential Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	0
Residential Real Estate [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0	0	0
Residential Real Estate [Member] | Extended Maturity [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0	0	0
Residential Real Estate [Member] | Extended Maturity [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 0	$ 0
Commercial Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		2	5
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 644	$ 10,857
Financing Receivable, Troubled Debt Restructuring		634	10,758
Financing Receivable Troubled Debt Restructuring Specific Reserve		$ 0	$ 0
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		2	4
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 644	$ 10,289
Financing Receivable, Troubled Debt Restructuring		634	10,263
Financing Receivable Troubled Debt Restructuring Specific Reserve		0	$ 0
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract			1
Financing Receivable, Troubled Debt Restructuring, Premodification			$ 568
Financing Receivable, Troubled Debt Restructuring			495
Financing Receivable Troubled Debt Restructuring Specific Reserve			0
Commercial Real Estate [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		644	10,857
Commercial Real Estate [Member] | Contractual Payment Modification [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		644	10,289
Commercial Real Estate [Member] | Contractual Payment Modification [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification			568
Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	0
Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	0
Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification			0
Commercial Real Estate [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	0
Commercial Real Estate [Member] | Extended Maturity [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 0	0
Commercial Real Estate [Member] | Extended Maturity [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification			$ 0
Loans To Individuals [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		7	14
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 173	$ 262
Financing Receivable, Troubled Debt Restructuring		144	224
Financing Receivable Troubled Debt Restructuring Specific Reserve		$ 0	$ 0
Loans To Individuals [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract		7	14
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 173	$ 262
Financing Receivable, Troubled Debt Restructuring		144	224
Financing Receivable Troubled Debt Restructuring Specific Reserve		0	0
Loans To Individuals [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		63	148
Loans To Individuals [Member] | Contractual Payment Modification [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		63	148
Loans To Individuals [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		110	114
Loans To Individuals [Member] | Contractual Interest Rate Reduction [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		110	114
Loans To Individuals [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		0	0
Loans To Individuals [Member] | Extended Maturity [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 0	$ 0