Loans - Loans Individually Evaluated for Impairment by Portfolio Class of Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	$ 4,194
With a specific allowance recorded, Recorded Investment	4,663
Recorded Investment	8,857
Related Allowance	1,996
Average Recorded Investment	10,710	$ 12,247
Interest Income Recognized	361	292
Interest Income Recognized Cash Basis	97	$ 188
Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	509
With no related allowance recorded, Unpaid Principal Balance	509
With no related allowance recorded, Average Recorded Investment	355
With no related allowance recorded, Interest Income Recognized	5
With no related allowance recorded, Interest Income Recognized Cash Basis	12
With a specific allowance recorded, Recorded Investment	60
With a specific allowance recorded, Unpaid Principal Balance	60
With a specific allowance recorded, Related Allowance	6
With a specific allowance recorded, Average Recorded Investment	15
With a specific allowance recorded, Interest Income Recognized Cash Basis	1
Recorded Investment	569
Unpaid Principal Balance	569
Related Allowance	6
Average Recorded Investment	370
Interest Income Recognized	5
Interest Income Recognized Cash Basis	13
Agricultural Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	2,280
With no related allowance recorded, Unpaid Principal Balance	2,385
With no related allowance recorded, Average Recorded Investment	2,048
With no related allowance recorded, Interest Income Recognized	25
With no related allowance recorded, Interest Income Recognized Cash Basis	6
With a specific allowance recorded, Average Recorded Investment	1,388
Recorded Investment	2,280
Unpaid Principal Balance	2,385
Average Recorded Investment	3,436
Interest Income Recognized	25
Interest Income Recognized Cash Basis	6
Agricultural [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	152
With no related allowance recorded, Unpaid Principal Balance	152
With no related allowance recorded, Average Recorded Investment	588
With no related allowance recorded, Interest Income Recognized Cash Basis	2
Recorded Investment	152
Unpaid Principal Balance	152
Average Recorded Investment	588
Interest Income Recognized Cash Basis	2
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	1,234
With no related allowance recorded, Unpaid Principal Balance	1,272
With no related allowance recorded, Average Recorded Investment	1,252
With no related allowance recorded, Interest Income Recognized	29
With no related allowance recorded, Interest Income Recognized Cash Basis	43
With a specific allowance recorded, Recorded Investment	2,874
With a specific allowance recorded, Unpaid Principal Balance	2,874
With a specific allowance recorded, Related Allowance	438
With a specific allowance recorded, Average Recorded Investment	3,176
With a specific allowance recorded, Interest Income Recognized	150
Recorded Investment	4,108
Unpaid Principal Balance	4,146
Related Allowance	438
Average Recorded Investment	4,428
Interest Income Recognized	179
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	17
With no related allowance recorded, Unpaid Principal Balance	417
With no related allowance recorded, Average Recorded Investment	135
With no related allowance recorded, Interest Income Recognized	2
With no related allowance recorded, Interest Income Recognized Cash Basis	10
With a specific allowance recorded, Recorded Investment	1,564
With a specific allowance recorded, Unpaid Principal Balance	1,564
With a specific allowance recorded, Related Allowance	1,551
With a specific allowance recorded, Average Recorded Investment	1,736
With a specific allowance recorded, Interest Income Recognized	149
With a specific allowance recorded, Interest Income Recognized Cash Basis	23
Recorded Investment	1,581
Unpaid Principal Balance	1,981
Related Allowance	1,551
Average Recorded Investment	1,871
Interest Income Recognized	151
Interest Income Recognized Cash Basis	33
Consumer [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	2
With no related allowance recorded, Unpaid Principal Balance	2
With no related allowance recorded, Average Recorded Investment	15
With no related allowance recorded, Interest Income Recognized	1
With a specific allowance recorded, Recorded Investment	165
With a specific allowance recorded, Unpaid Principal Balance	165
With a specific allowance recorded, Related Allowance	1
With a specific allowance recorded, Average Recorded Investment	2
Recorded Investment	167
Unpaid Principal Balance	167
Related Allowance	1
Average Recorded Investment	17
Interest Income Recognized	$ 1

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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