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Loans Held for Investment - Schedule of Recorded Investment in Past Due Loans (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | $ 0.5 |  | $ 19.1
Nonaccrual loans | 116.5 |  | 56.9
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 17,377.3 |  | 17,844.9
Accrued interest reversal | (1.5) | $ (1.8) |
Financing Receivable, Excluding Accrued Interest, Nonaccrual | 0.0 | $ 0.0 |
Financing Receivable, Nonaccrual, Interest Income | 0.4 |  |
30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Nonaccrual loans | 14.8 |  | 13.5
60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Nonaccrual loans | 28.3 |  | 6.2
Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Nonaccrual loans | 76.9 |  | 40.5
Commercial |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 29.9 |  | 7.7
Nonaccrual loans | 82.9 |  | 55.4
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 9,196.1 |  | 9,263.2
Commercial | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.4 |  | 4.9
Commercial | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 28.5 |  | 2.8
Commercial | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Commercial | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 9,083.3 |  | 9,200.1
Total construction loans |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 3.6 |  | 3.7
Nonaccrual loans | 4.0 |  | 3.3
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 1,097.3 |  | 1,244.6
Total construction loans | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 3.6 |  | 3.7
Total construction loans | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Total construction loans | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Total construction loans | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1,089.7 |  | 1,237.6
Residential |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 11.8 |  | 9.7
Nonaccrual loans | 16.6 |  | 15.4
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 2,161.4 |  | 2,191.6
Residential | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 10.7 |  | 6.6
Residential | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.4 |  | 2.7
Residential | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.7 |  | 0.4
Residential | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 2,133.0 |  | 2,166.5
Agricultural |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 17.2 |  | 10.4
Nonaccrual loans | 20.5 |  | 5.3
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 678.1 |  | 701.1
Agricultural | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 10.1 |  | 7.6
Agricultural | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 7.0 |  | 2.8
Agricultural | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.1 |  | 0.0
Agricultural | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 640.4 |  | 685.4
Total real estate |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 62.5 |  | 31.5
Nonaccrual loans | 124.0 |  | 79.4
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 13,132.9 |  | 13,400.5
Total real estate | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 25.8 |  | 22.8
Total real estate | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 35.9 |  | 8.3
Total real estate | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.8 |  | 0.4
Total real estate | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 12,946.4 |  | 13,289.6
Indirect consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 8.9 |  | 11.7
Nonaccrual loans | 4.5 |  | 3.9
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 680.2 |  | 725.0
Indirect consumer | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 7.2 |  | 8.4
Indirect consumer | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.6 |  | 2.6
Indirect consumer | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.1 |  | 0.7
Indirect consumer | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 666.8 |  | 709.4
Credit Card Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.8 |  | 2.2
Nonaccrual loans | 0.0 |  | 0.0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 74.2 |  | 77.6
Credit Card Receivable [Member] | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.7 |  | 0.7
Credit Card Receivable [Member] | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.4 |  | 0.5
Credit Card Receivable [Member] | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.7 |  | 1.0
Credit Card Receivable [Member] | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 72.4 |  | 75.4
Total consumer loans |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 11.4 |  | 15.0
Nonaccrual loans | 5.1 |  | 4.5
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 886.8 |  | 936.6
Total consumer loans | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 8.4 |  | 9.7
Total consumer loans | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 2.2 |  | 3.3
Total consumer loans | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.8 |  | 2.0
Total consumer loans | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 870.3 |  | 917.1
Commercial |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 7.0 |  | 14.8
Nonaccrual loans | 31.3 |  | 33.5
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 2,770.6 |  | 2,829.4
Commercial | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 4.4 |  | 11.2
Commercial | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.3 |  | 3.0
Commercial | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.3 |  | 0.6
Commercial | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 2,732.3 |  | 2,781.1
Agricultural |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 12.3 |  | 5.2
Nonaccrual loans | 31.5 |  | 20.9
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 595.8 |  | 687.9
Agricultural | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 11.0 |  | 2.4
Agricultural | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.2 |  | 2.8
Agricultural | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.1 |  | 0.0
Agricultural | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 552.0 |  | 661.8
Other, including overdrafts |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Nonaccrual loans | 0.0 |  | 0.0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 1.8 |  | 1.6
Other, including overdrafts | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Other, including overdrafts | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Other, including overdrafts | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.0
Other, including overdrafts | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 1.8 |  | 1.6
Loans And Leases Held For Investment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 93.2 |  | 66.5
Nonaccrual loans | 191.9 |  | 138.3
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 17,387.9 |  | 17,856.0
Loans And Leases Held For Investment [Member] | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 49.6 |  | 46.1
Loans And Leases Held For Investment [Member] | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 40.6 |  | 17.4
Loans And Leases Held For Investment [Member] | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 3.0 |  | 3.0
Loans And Leases Held For Investment [Member] | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 17,102.8 |  | 17,651.2
Consumer Loan |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.7 |  | 1.1
Nonaccrual loans | 0.6 |  | 0.6
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process | 132.4 |  | 134.0
Consumer Loan | 30 to 59 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.5 |  | 0.6
Consumer Loan | 60 to 89 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.2 |  | 0.2
Consumer Loan | Equal to or Greater than 90 Days Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | 0.0 |  | 0.3
Consumer Loan | Financial Asset, Not Past Due |  |  |
Loans and Leases Receivable Recorded Investment, Past Due [Line Items] |  |  |
Financing Receivable, Loan in Process | $ 131.1 |  | $ 132.3

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