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Loans Held for Investment - Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2022 | Dec. 31, 2021
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | $ (15.2) | $ (61.3) |  |
Accounts Receivable, Allowance for Credit Loss | 226.1 | 247.2 | $ 220.1 | $ 122.3
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) | 12.2 | 57.3 |  |
Impaired Financing Receivable, Interest Income, Accrual Method | 0.0 | 0.0 |  |
Total real estate loans |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (13.4) | (38.5) |  |
Accounts Receivable, Allowance for Credit Loss | 147.5 | 169.6 | 138.7 | 69.3
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 13,534.6 |  | 13,456.2 |
Commercial |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | 0.8 | (19.1) |  |
Accounts Receivable, Allowance for Credit Loss | 54.4 | 58.2 | 54.9 | 31.6
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 3,028.0 |  | 2,882.6 |
Agricultural |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | 1.1 | 0.5 |  |
Accounts Receivable, Allowance for Credit Loss | 2.4 | (1.0) | 3.2 | 0.3
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 660.4 |  | 708.3 |
Non-owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (1.3) | (6.7) |  |
Accounts Receivable, Allowance for Credit Loss | 26.0 | 45.2 | 27.2 | 17.3
Owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | 0.2 | (4.6) |  |
Accounts Receivable, Allowance for Credit Loss | 17.6 | 25.2 | 19.5 | 13.3
Commercial |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (8.2) | (22.7) |  |
Accounts Receivable, Allowance for Credit Loss | 78.6 | 125.0 | 74.6 | 43.9
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 8,680.8 |  | 8,528.6 |
Residential construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (0.1) | (0.9) |  |
Accounts Receivable, Allowance for Credit Loss | 3.7 | 3.3 | 3.6 | 2.4
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 471.4 |  | 516.2 |
Commercial construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (5.9) | (4.0) |  |
Accounts Receivable, Allowance for Credit Loss | 37.1 | 10.2 | 31.2 | 6.0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 1,053.1 |  | 1,042.0 |
Total construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (6.3) | (4.1) |  |
Accounts Receivable, Allowance for Credit Loss | 42.4 | 14.0 | 36.1 | 8.9
Residential 1-4 family |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | 0.2 | (5.2) |  |
Accounts Receivable, Allowance for Credit Loss | 20.2 | 18.7 | 20.5 | 13.4
Residential |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | (0.1) | (5.3) |  |
Accounts Receivable, Allowance for Credit Loss | 21.7 | 20.1 | 22.1 | 14.6
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 2,191.1 |  | 2,188.3 |
Agricultural |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Provision charged to operating expense | 1.2 | (6.4) |  |
Accounts Receivable, Allowance for Credit Loss | 4.8 | $ 10.5 | 5.9 | $ 1.9
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 769.7 |  | 794.9 |
Collateral [Member] |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 59.5 |  | 39.1 |
Collateral [Member] | Commercial |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 7.5 |  | 4.6 |
Collateral [Member] | Agricultural |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 2.6 |  | 7.3 |
Collateral [Member] | Non-owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 13.8 |  | 4.4 |
Collateral [Member] | Owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 12.1 |  | 13.0 |
Collateral [Member] | Residential construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 17.9 |  | 3.2 |
Collateral [Member] | Commercial construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.5 |  |  |
Collateral [Member] | Residential 1-4 family |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.5 |  | 0.5 |
Collateral [Member] | Agricultural |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 4.6 |  | 6.1 |
Business Assets [Member] | Collateral [Member] |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 9.1 |  | 7.1 |
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 | 5.4 |  | 3.1 |
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 | 2.1 |  | 2.1 |
Business Assets [Member] | Collateral [Member] | Non-owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 1.6 |  | 1.7 |
Business Assets [Member] | Collateral [Member] | Owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |
Business Assets [Member] | Collateral [Member] | Residential construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  | 0.0 |
Business Assets [Member] | Collateral [Member] | Commercial construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.0 |  |  |
Business Assets [Member] | Collateral [Member] | Residential 1-4 family |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 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 |  | 0.2 |
Real Property [Member] | Collateral [Member] |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 50.4 |  | 32.0 |
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 | 2.1 |  | 1.5 |
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 | 0.5 |  | 5.2 |
Real Property [Member] | Collateral [Member] | Non-owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 12.2 |  | 2.7 |
Real Property [Member] | Collateral [Member] | Owner occupied |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 12.1 |  | 13.0 |
Real Property [Member] | Collateral [Member] | Residential construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 17.9 |  | 3.2 |
Real Property [Member] | Collateral [Member] | Commercial construction |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.5 |  |  |
Real Property [Member] | Collateral [Member] | Residential 1-4 family |  |  |  |
Loans and Leases Receivable Recorded Investment, Impaired [Line Items] |  |  |  |
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss | 0.5 |  | 0.5 |
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 | $ 4.6 |  | $ 5.9 |

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