Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Loans Receivable - Summary of Portfolio Segments and Classes of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	$ 668,672		$ 236,840
Deferred fees	(274)		(256)
Allowance for loan losses	(3,335)	$ (2,875)	(2,789)	$ (2,838)	$ (2,794)	$ (2,702)
Total	665,063		233,795
Paycheck Protection Program ("PPP") Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	39,794		0
Agriculture Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	8,873		11,246
Commercial Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	83,742		21,534
Commercial Real Estate Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	309,079		27,261
Residential Real Estate Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	216,526		167,536
Consumer Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	4,309		2,514
Municipal Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable	$ 6,351		$ 6,749