Loans Held for Sale - By Segment (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	$ 70.8	$ 73.6
Agricultural
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	20.6	20.5
Commercial
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	16.7	19.5
Total construction loans
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	0.7	1.3
Residential Mortgage
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	3.3	3.5
Agricultural
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	16.0	17.8
Total real estate
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	41.4	43.2
Consumer Loan
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	2.3	2.5
Total consumer loans
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	2.3	2.5
Commercial
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	6.5	7.4
Residential Mortgage, at fair value
Debt Securities, Available-for-sale [Line Items]
Loans held for sale ($4.7 and $1.1 of which is recorded at fair value at March 31, 2026 and December 31, 2025, respectively)	$ 4.7	$ 1.1