Allowances for Loan Losses - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Financing Receivable, Impaired [Line Items]
With an allowance recorded, Recorded Investment					$ 0
With an allowance recorded, Unpaid Principal Balance					0
With an allowance recorded, Related Allowance	$ 0		$ 0		0
Total, Recorded Investment	8,297		8,297		751
Total, Unpaid Principal Balance	8,441		8,441		840
Total, Related Allowance	0		0		0
With no related allowance recorded, Average Recorded Investment	8,541	$ 213	8,809	$ 225
With no related allowance recorded, Interest Recognized	96	4	195	8
With an allowance recorded, Average Recorded Investment	0	0	0	0
With an allowance recorded, Interest Recognized	0	0	0	0
Total, Average Recorded Investment	8,541	213	8,809	225
Total, Interest Recognized	96	4	195	8
Agriculture Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	200		200		0
With no related allowance recorded, Unpaid Principal Balance	200		200		0
With an allowance recorded, Recorded Investment	0		0		0
With an allowance recorded, Unpaid Principal Balance	0		0		0
With an allowance recorded, Related Allowance	0		0		0
Total, Recorded Investment	200		200		0
Total, Unpaid Principal Balance	200		200		0
Total, Related Allowance	0		0		0
With no related allowance recorded, Average Recorded Investment	237	0	242	0
With no related allowance recorded, Interest Recognized	3	0	6	0
With an allowance recorded, Average Recorded Investment	0	0	0	0
With an allowance recorded, Interest Recognized	0	0	0	0
Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	2,451		2,451		42
With no related allowance recorded, Unpaid Principal Balance	2,471		2,471		61
With an allowance recorded, Recorded Investment	0		0		0
With an allowance recorded, Unpaid Principal Balance	0		0		0
With an allowance recorded, Related Allowance	0		0		0
Total, Recorded Investment	2,451		2,451		42
Total, Unpaid Principal Balance	2,471		2,471		61
Total, Related Allowance	0		0		0
With no related allowance recorded, Average Recorded Investment	4,706	0	4,935	0
With no related allowance recorded, Interest Recognized	66	0	132	0
With an allowance recorded, Average Recorded Investment	0		0	0
With an allowance recorded, Interest Recognized	0	0	0	0
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	2,501		2,501
With no related allowance recorded, Unpaid Principal Balance	2,501		2,501
With an allowance recorded, Recorded Investment	0		0		0
With an allowance recorded, Unpaid Principal Balance	0		0		0
With an allowance recorded, Related Allowance	0		0		0
Total, Recorded Investment	2,501		2,501		0
Total, Unpaid Principal Balance	2,501		2,501		0
Total, Related Allowance	0		0		0
With no related allowance recorded, Average Recorded Investment	455	0	461	0
With no related allowance recorded, Interest Recognized	4	0	9	0
With an allowance recorded, Average Recorded Investment	0	0	0	0
With an allowance recorded, Interest Recognized	0	0	0	0
Residential Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	3,145		3,145		709
With no related allowance recorded, Unpaid Principal Balance	3,269		3,269		779
With an allowance recorded, Recorded Investment	0		0		0
With an allowance recorded, Unpaid Principal Balance	0		0		0
With an allowance recorded, Related Allowance	0		0		0
Total, Recorded Investment	3,145		3,145		709
Total, Unpaid Principal Balance	3,269		3,269		779
Total, Related Allowance	0		0		0
With no related allowance recorded, Average Recorded Investment	3,143	213	3,171	225
With no related allowance recorded, Interest Recognized	23	4	48	8
With an allowance recorded, Average Recorded Investment	0	0	0	0
With an allowance recorded, Interest Recognized	0	0	0	0
Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	0		0
With no related allowance recorded, Unpaid Principal Balance	0		0
With an allowance recorded, Recorded Investment	0		0		0
With an allowance recorded, Unpaid Principal Balance	0		0		0
With an allowance recorded, Related Allowance	0		0		0
Total, Recorded Investment	0		0		0
Total, Unpaid Principal Balance	0		0		0
Total, Related Allowance	0		0		0
With no related allowance recorded, Average Recorded Investment		0		0
With no related allowance recorded, Interest Recognized		0		0
With an allowance recorded, Average Recorded Investment	0	0	0	0
With an allowance recorded, Interest Recognized	0	0	0	0
Municipal Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	0		0
With no related allowance recorded, Unpaid Principal Balance	0		0
With an allowance recorded, Recorded Investment	0		0		0
With an allowance recorded, Unpaid Principal Balance	0		0		0
With an allowance recorded, Related Allowance	0		0		0
Total, Recorded Investment	0		0		0
Total, Unpaid Principal Balance	0		0		0
Total, Related Allowance	0		0		$ 0
With no related allowance recorded, Average Recorded Investment		0		0
With no related allowance recorded, Interest Recognized		0		0
With an allowance recorded, Average Recorded Investment	0	0	0	0
With an allowance recorded, Interest Recognized	$ 0	$ 0	$ 0	$ 0