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Loans Held for Investment - Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024 | Dec. 31, 2024
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) | $ 0.1 | $ 18.6 | $ 20.3 | $ 27.0 |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 16,353.4 |  | 16,353.4 |  | $ 17,844.9
Collateral [Member] |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 158.3 |  | 158.3 |  | 97.6
Collateral [Member] | Total real estate |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 102.5 |  | 102.5 |  | 55.0
Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 35.2 |  | 35.2 |  | 22.2
Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 20.6 |  | 20.6 |  | 20.4
Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 78.8 |  | 78.8 |  | 47.3
Collateral [Member] | Residential |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 2.7 |  | 2.7 |  | 2.7
Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 17.0 |  | 17.0 |  | 1.8
Collateral [Member] | Total construction loans |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 4.0 |  | 4.0 |  | 3.2
Business Assets [Member] | Collateral [Member] |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 39.3 |  | 39.3 |  | 20.3
Business Assets [Member] | Collateral [Member] | Total real estate |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Business Assets [Member] | Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 25.9 |  | 25.9 |  | 20.3
Business Assets [Member] | Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 13.4 |  | 13.4 |  | 0.0
Business Assets [Member] | Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Business Assets [Member] | Collateral [Member] | Residential |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Business Assets [Member] | Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Business Assets [Member] | Collateral [Member] | Total construction loans |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Real Property [Member] | Collateral [Member] |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 118.1 |  | 118.1 |  | 76.4
Real Property [Member] | Collateral [Member] | Total real estate |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 102.5 |  | 102.5 |  | 55.0
Real Property [Member] | Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 8.5 |  | 8.5 |  | 1.1
Real Property [Member] | Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 7.1 |  | 7.1 |  | 20.3
Real Property [Member] | Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 78.8 |  | 78.8 |  | 47.3
Real Property [Member] | Collateral [Member] | Residential |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 2.7 |  | 2.7 |  | 2.7
Real Property [Member] | Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 17.0 |  | 17.0 |  | 1.8
Real Property [Member] | Collateral [Member] | Total construction loans |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 4.0 |  | 4.0 |  | 3.2
Other Property [Member] | Collateral [Member] |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.9 |  | 0.9 |  | 0.9
Other Property [Member] | Collateral [Member] | Total real estate |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Other Property [Member] | Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.8 |  | 0.8 |  | 0.8
Other Property [Member] | Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.1 |  | 0.1 |  | 0.1
Other Property [Member] | Collateral [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Other Property [Member] | Collateral [Member] | Residential |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Other Property [Member] | Collateral [Member] | Agricultural |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |  | 0.0
Other Property [Member] | Collateral [Member] | Total construction loans |  |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | $ 0.0 |  | $ 0.0 |  | $ 0.0

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