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Loans Held for Investment - Schedule of Allowance for Credit Losses for Loans Held for Investment (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | $ 135.5 | $ 146.1 | $ 144.3 | $ 73.0
Provision charged to operating expense | 0.0 | (5.2) | 5.1 | (53.7)
Loans Charged-Off | (2.1) | (6.4) | (11.8) | (15.1)
Ending balance | 135.1 | 145.5 | 135.1 | 145.5
Financing Receivable, Allowance for Credit Loss, Recovery | 1.5 | 1.8 | 7.2 | 5.1
Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 30.0
Commercial Real Estate Non Owner Occupied Loans [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 22.9 | 23.6 | 25.5 | 8.8
Provision charged to operating expense | (1.1) | (1.5) | (1.6) | (11.4)
Loans Charged-Off | 0.0 | 0.0 | 0.0 | 0.0
Ending balance | 24.0 | 25.2 | 24.0 | 25.2
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.1 | 0.1 | 0.1
Commercial Real Estate Non Owner Occupied Loans [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 4.9
Agricultural Financing Receivable [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 0.4 | 0.9 | 0.7 | 1.6
Provision charged to operating expense | 0.0 | 0.0 | (0.1) | 0.0
Loans Charged-Off | 0.0 | 0.0 | (0.2) | (0.1)
Ending balance | 0.4 | 0.9 | 0.4 | 0.9
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.0 | 0.0
Agricultural Financing Receivable [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (0.6)
Commercial and Floor Plans [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 29.0 | 41.0 | 34.2 | 25.5
Provision charged to operating expense | (0.3) | (1.2) | (4.9) | (20.0)
Loans Charged-Off | (0.1) | (3.3) | (2.2) | (4.7)
Ending balance | 29.4 | 36.7 | 29.4 | 36.7
Financing Receivable, Allowance for Credit Loss, Recovery | 0.2 | 0.2 | 2.3 | 1.0
Commercial and Floor Plans [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (5.1)
Commercial Real Estate Owner Occupied [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 16.6 | 19.1 | 18.3 | 10.0
Provision charged to operating expense | (0.6) | (0.1) | 0.0 | (5.7)
Loans Charged-Off | 0.0 | (0.2) | (2.3) | (0.3)
Ending balance | 16.0 | 19.1 | 16.0 | 19.1
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.1 | 0.0 | 0.2
Commercial Real Estate Owner Occupied [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 3.5
Commercial Real Estate Multi-family [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 11.6 | 8.5 | 11.0 | 0.7
Provision charged to operating expense | (0.2) | (2.3) | (0.8) | (3.2)
Loans Charged-Off | 0.0 | 0.0 | 0.0 | 0.0
Ending balance | 11.8 | 10.8 | 11.8 | 10.8
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.0 | 0.0
Commercial Real Estate Multi-family [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 6.9
Commercial real estate |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 51.1 | 51.2 | 54.8 | 19.5
Provision charged to operating expense | (0.7) | (3.9) | (0.8) | (20.3)
Loans Charged-Off | 0.0 | (0.2) | (2.3) | (0.3)
Ending balance | 51.8 | 55.1 | 51.8 | 55.1
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.2 | 0.1 | 0.3
Commercial real estate | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 15.3
Land Acquisition And Development Construction Financing Receivable [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 1.0 | 1.5 | 1.3 | 1.9
Provision charged to operating expense | (0.2) | (0.5) | (0.8) | (0.3)
Loans Charged-Off | 0.0 | 0.0 | (0.1) | (0.5)
Ending balance | 0.9 | 1.2 | 0.9 | 1.2
Financing Receivable, Allowance for Credit Loss, Recovery | 0.1 | 0.2 | 0.5 | 0.2
Land Acquisition And Development Construction Financing Receivable [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (0.1)
Residential construction |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 1.5 | 1.3 | 1.6 | 1.5
Provision charged to operating expense | (0.3) | (0.3) | (0.3) | (1.0)
Loans Charged-Off | 0.0 | 0.0 | (0.1) | 0.0
Ending balance | 1.8 | 1.6 | 1.8 | 1.6
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.0 | 0.0
Residential construction | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (0.9)
Commercial construction |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 8.0 | 6.3 | 7.3 | 2.7
Provision charged to operating expense | (1.3) | (0.8) | (0.6) | (3.1)
Loans Charged-Off | 0.0 | 0.0 | (0.1) | 0.0
Ending balance | 6.7 | 7.1 | 6.7 | 7.1
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.1 | 0.0
Commercial construction | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 1.3
Construction Loans [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 10.5 | 9.1 | 10.2 | 6.1
Provision charged to operating expense | (1.2) | (0.6) | (1.1) | (3.8)
Loans Charged-Off | 0.0 | 0.0 | (0.3) | (0.5)
Ending balance | 9.4 | 9.9 | 9.4 | 9.9
Financing Receivable, Allowance for Credit Loss, Recovery | 0.1 | 0.2 | 0.6 | 0.2
Construction Loans [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 0.3
Residential Real Estate 1-4 Family [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 13.4 | 10.3 | 11.4 | 1.8
Provision charged to operating expense | (0.2) | (1.1) | (1.8) | (3.3)
Loans Charged-Off | 0.0 | 0.0 | 0.0 | 0.0
Ending balance | 13.2 | 9.2 | 13.2 | 9.2
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.0 | 0.1
Residential Real Estate 1-4 Family [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 10.6
Home Equity Line of Credit [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 1.4 | 1.5 | 1.4 | 1.0
Provision charged to operating expense | (0.1) | 0.0 | (0.2) | (0.1)
Loans Charged-Off | 0.0 | 0.0 | (0.1) | 0.0
Ending balance | 1.4 | 1.5 | 1.4 | 1.5
Financing Receivable, Allowance for Credit Loss, Recovery | 0.1 | 0.0 | 0.3 | 0.1
Residential Real Estate [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 14.8 | 11.8 | 12.8 | 2.8
Provision charged to operating expense | (0.3) | (1.1) | (1.6) | (3.4)
Loans Charged-Off | 0.0 | 0.0 | (0.1) | 0.0
Ending balance | 14.6 | 10.7 | 14.6 | 10.7
Financing Receivable, Allowance for Credit Loss, Recovery | 0.1 | 0.0 | 0.3 | 0.2
Residential Real Estate [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 11.1
Agricultural Real Estate Financing Receivable [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 3.0 | 3.1 | 2.7 | 0.5
Provision charged to operating expense | (0.1) | (0.2) | (0.4) | (0.6)
Loans Charged-Off | 0.0 | 0.0 | 0.0 | 0.0
Ending balance | 3.1 | 2.9 | 3.1 | 2.9
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.0 | 0.0
Agricultural Real Estate Financing Receivable [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 1.8
Real Estate Financing Receivable [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 79.4 | 75.2 | 80.5 | 28.9
Provision charged to operating expense | (0.7) | (3.2) | (0.1) | (21.3)
Loans Charged-Off | 0.0 | (0.2) | (2.7) | (0.8)
Ending balance | 78.9 | 78.6 | 78.9 | 78.6
Financing Receivable, Allowance for Credit Loss, Recovery | 0.2 | 0.4 | 1.0 | 0.7
Real Estate Financing Receivable [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 28.5
Consumer Indirect Financing Receivable [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 15.8 | 16.4 | 16.7 | 4.5
Provision charged to operating expense | (0.1) | (0.7) | (0.3) | (5.1)
Loans Charged-Off | (0.8) | (0.8) | (2.9) | (3.2)
Ending balance | 15.4 | 17.0 | 15.4 | 17.0
Financing Receivable, Allowance for Credit Loss, Recovery | 0.5 | 0.7 | 1.9 | 1.8
Consumer Indirect Financing Receivable [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 8.8
Direct consumer |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 4.6 | 5.1 | 4.6 | 2.9
Provision charged to operating expense | (0.5) | (0.6) | (1.2) | (1.3)
Loans Charged-Off | (0.8) | (1.1) | (2.0) | (3.1)
Ending balance | 4.7 | 4.8 | 4.7 | 4.8
Financing Receivable, Allowance for Credit Loss, Recovery | 0.4 | 0.2 | 0.9 | 0.7
Direct consumer | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 3.0
Credit Card Receivable [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 1.6 | 2.0 | 2.6 | 2.5
Provision charged to operating expense | (0.4) | (0.6) | 0.0 | (1.0)
Loans Charged-Off | (0.4) | (0.6) | (1.4) | (2.2)
Ending balance | 1.8 | 2.2 | 1.8 | 2.2
Financing Receivable, Allowance for Credit Loss, Recovery | 0.2 | 0.2 | 0.6 | 0.6
Credit Card Receivable [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 0.3
Consumer |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 22.0 | 23.5 | 23.9 | 9.9
Provision charged to operating expense | (0.8) | (1.9) | (0.9) | (7.4)
Loans Charged-Off | (2.0) | (2.5) | (6.3) | (8.5)
Ending balance | 21.9 | 24.0 | 21.9 | 24.0
Financing Receivable, Allowance for Credit Loss, Recovery | 1.1 | 1.1 | 3.4 | 3.1
Consumer | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | 12.1
Commercial Purpose secured by 1-4 Family [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 4.4 | 5.1 | 4.7 | 5.9
Provision charged to operating expense | (0.2) | (0.2) | (0.8) | (2.8)
Loans Charged-Off | 0.0 | 0.0 | (0.1) | (0.1)
Ending balance | 4.2 | 5.0 | 4.2 | 5.0
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.1 | 0.4 | 0.2
Commercial Purpose secured by 1-4 Family [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (3.8)
Commercial Borrower [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 0.3 | 0.4 | 0.3 | 1.2
Provision charged to operating expense | 0.0 | (0.3) | (0.2) | (1.0)
Loans Charged-Off | 0.0 | (0.4) | (0.3) | (0.9)
Ending balance | 0.3 | 0.3 | 0.3 | 0.3
Financing Receivable, Allowance for Credit Loss, Recovery | 0.0 | 0.0 | 0.1 | 0.1
Commercial Borrower [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (1.1)
Commercial Portfolio Segment [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 33.7 | 46.5 | 39.2 | 32.6
Provision charged to operating expense | (0.1) | (1.1) | (5.5) | (23.8)
Loans Charged-Off | (0.1) | (3.7) | (2.6) | (5.7)
Ending balance | 33.9 | 42.0 | 33.9 | 42.0
Financing Receivable, Allowance for Credit Loss, Recovery | 0.2 | 0.3 | 2.8 | 1.3
Commercial Portfolio Segment [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | (10.0)
Agriculture Portfolio Segment [Member] |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance | 0.4 | 0.9 |  |
Provision charged to operating expense | 0.0 | 0.0 |  | 0.0
Loans Charged-Off | 0.0 | 0.0 |  | (0.1)
Ending balance | 0.4 | 0.9 | $ 0.4 | 0.9
Financing Receivable, Allowance for Credit Loss, Recovery | $ 0.0 | $ 0.0 |  | 0.0
Agriculture Portfolio Segment [Member] | Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity |  |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |  |
Beginning balance |  |  |  | $ (0.6)

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