Allowances for Loan Losses - Summary of Aging Analysis of the Recorded Investment of Past-Due Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	$ 4,365	$ 5,556
Loans receivable	790,181	715,039
Total > 90 Days and Accruing	0	762
Agriculture Loans [Member]
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	0
Loans receivable	7,710	9,341
Total > 90 Days and Accruing	0
Commercial and PPP Loans [Member]
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	0	512
Loans receivable	90,979	122,378
Total > 90 Days and Accruing	0
Commercial Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	4,365	4,394
Loans receivable	435,588	338,749
Total > 90 Days and Accruing	0
Residential Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	0	650
Loans receivable	241,401	231,302
Total > 90 Days and Accruing	0	762
Consumer Loans [Member]
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	0
Loans receivable	8,689	7,087
Total > 90 Days and Accruing	0
Municipal Loans [Member]
Financing Receivable, Past Due [Line Items]
Purchased Credit Impaired Loans	0
Loans receivable	5,814	6,182
Total > 90 Days and Accruing	0
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	2,096	1,852
30-59 Days Past Due [Member] | Agriculture Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	154	83
30-59 Days Past Due [Member] | Commercial and PPP Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	0	66
30-59 Days Past Due [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	460	245
30-59 Days Past Due [Member] | Residential Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	1,467	1,427
30-59 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	15	31
30-59 Days Past Due [Member] | Municipal Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross
60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	373	213
60-89 Days Past Due [Member] | Agriculture Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross
60-89 Days Past Due [Member] | Commercial and PPP Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	21
60-89 Days Past Due [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	140
60-89 Days Past Due [Member] | Residential Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	210	211
60-89 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	2	2
60-89 Days Past Due [Member] | Municipal Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	0
90 Days or Greater Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	338	869
90 Days or Greater Past Due [Member] | Agriculture Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross
90 Days or Greater Past Due [Member] | Commercial and PPP Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross
90 Days or Greater Past Due [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	0
90 Days or Greater Past Due [Member] | Residential Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	338	869
90 Days or Greater Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross
90 Days or Greater Past Due [Member] | Municipal Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	0
Total Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	2,807	2,934
Total Past Due [Member] | Agriculture Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	154	83
Total Past Due [Member] | Commercial and PPP Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	21	66
Total Past Due [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	600	245
Total Past Due [Member] | Residential Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	2,015	2,507
Total Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	17	33
Total Past Due [Member] | Municipal Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross
Current [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	783,009	706,549
Current [Member] | Agriculture Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	7,556	9,258
Current [Member] | Commercial and PPP Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	90,958	121,800
Current [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	430,623	334,110
Current [Member] | Residential Real Estate Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	239,386	228,145
Current [Member] | Consumer Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	8,672	7,054
Current [Member] | Municipal Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, Gross	$ 5,814	$ 6,182