v3.25.2
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