Servicing - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Loan Strata	Dec. 31, 2022 USD ($)
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Valuation allowance	$ 7
1-4 Family Real Estate Loans [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Loans serviced for others unpaid principal amount	367,800	$ 375,600
Capitalized service right assets included in other assets	3,500	3,500
Fair value of the capitalized servicing rights	$ 5,500	$ 5,100
Number of loans | Loan	3,749
Number of strata which included loan | Strata	2
Prepayment rate	6.30%	7.70%
Discount yield	5.70%
Valuation allowance	$ 2
Agricultural Real Estate Loans [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Loans serviced for others unpaid principal amount	135,800
Capitalized service right assets included in other assets	2,200
Fair value of the capitalized servicing rights	$ 2,600
Number of loans | Loan	593
Number of strata which included loan | Strata	11
Discount yield	8.66%	5.94%
Valuation allowance	$ 5
Two 1-4 Family Real Estate Strata [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Number of loans | Loan	103
Eleven Agricultural Real Estate Strata [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Number of loans | Loan	41