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Loans - Schedule of Recorded Investment in Past Due Loans by Class (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total loans | $ 9,807.5 | $ 8,930.7 |
Impaired Financing Receivable, Interest Income, Accrual Method | 0.0 | 0.3 | $ 0.3
Financing Receivable, Allowance for Credit Loss, Writeoff | 0.0 |  |
Loans and Leases Receivable, Nonperforming, Accrual of Interest | 0.0 |  |
Commercial Real Estate Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 12.8 | 7.2 |
Current Loans | 3,720.8 | 3,467.6 |
Non-accrual Loans | 9.6 | 13.0 |
Loans held for investment | 3,743.2 | 3,487.8 |
Land Acquisition And Development Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 3.7 | 1.8 |
Current Loans | 260.6 | 298.9 |
Non-accrual Loans | 0.7 | 1.4 |
Loans held for investment | 265.0 | 302.1 |
Total loans | 265.0 |  |
Residential Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.9 | 2.3 |
Current Loans | 247.9 | 241.8 |
Non-accrual Loans | 1.1 | 0.0 |
Loans held for investment | 250.9 | 244.1 |
Total loans | 250.9 |  |
Commercial Real Estate Construction [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 12.2 | 0.0 |
Current Loans | 511.2 | 431.0 |
Non-accrual Loans | 0.1 | 0.5 |
Loans held for investment | 523.5 | 431.5 |
Total loans | 523.5 |  |
Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 17.8 | 4.1 |
Current Loans | 1,019.7 | 971.7 |
Non-accrual Loans | 1.9 | 1.9 |
Loans held for investment | 1,039.4 | 977.7 |
Residential Mortgage [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 6.8 | 6.3 |
Current Loans | 1,384.9 | 1,235.2 |
Non-accrual Loans | 4.6 | 4.6 |
Loans held for investment | 1,396.3 | 1,246.1 |
Agricultural Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 2.0 | 1.3 |
Current Loans | 212.4 | 220.1 |
Non-accrual Loans | 6.2 | 5.2 |
Loans held for investment | 220.6 | 226.6 |
Total loans | 220.6 |  |
Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 39.4 | 18.9 |
Current Loans | 6,337.8 | 5,894.6 |
Non-accrual Loans | 22.3 | 24.7 |
Loans held for investment | 6,399.5 | 5,938.2 |
Impaired Financing Receivable, Interest Income, Accrual Method |  | 0.1 | 0.1
Indirect consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 8.9 | 10.0 |
Current Loans | 794.3 | 773.0 |
Non-accrual Loans | 1.9 | 1.6 |
Loans held for investment | 805.1 | 784.6 |
Total loans | 805.1 |  |
Other consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.2 | 1.8 |
Current Loans | 149.0 | 176.7 |
Non-accrual Loans | 0.4 | 0.5 |
Loans held for investment | 150.6 | 179.0 |
Total loans | 150.6 |  |
Credit card consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.6 | 2.1 |
Current Loans | 68.6 | 79.5 |
Non-accrual Loans | 0.0 | 0.0 |
Loans held for investment | 70.2 | 81.6 |
Total consumer loans |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 11.7 | 13.9 |
Current Loans | 1,011.9 | 1,029.2 |
Non-accrual Loans | 2.3 | 2.1 |
Loans held for investment | 1,025.9 | 1,045.2 |
Commercial Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 9.2 | 9.7 |
Current Loans | 2,132.9 | 1,650.3 |
Non-accrual Loans | 11.8 | 13.7 |
Loans held for investment | 2,153.9 | 1,673.7 |
Impaired Financing Receivable, Interest Income, Accrual Method |  | 0.2 | 0.2
Other, including overdrafts |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Current Loans | 1.6 | 0.0 |
Non-accrual Loans | 0.0 | 0.0 |
Loans held for investment | 1.6 | 0.0 |
Loans held for investment |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 62.7 | 43.5 |
Current Loans | 9,726.3 | 8,849.8 |
Non-accrual Loans | 39.5 | 42.9 |
Loans held for investment | 9,828.5 | 8,936.2 |
Agricultural Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 2.4 | 1.0 |
Current Loans | 242.1 | 275.7 |
Non-accrual Loans | 3.1 | 2.4 |
Loans held for investment | 247.6 | 279.1 |
Impaired Financing Receivable, Interest Income, Accrual Method |  | 0.0 | $ 0.0
Financing Receivables, 30 to 59 Days Past Due | Commercial Real Estate Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 7.6 | 5.5 |
Financing Receivables, 30 to 59 Days Past Due | Land Acquisition And Development Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 2.5 | 0.7 |
Financing Receivables, 30 to 59 Days Past Due | Residential Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.5 | 1.5 |
Financing Receivables, 30 to 59 Days Past Due | Commercial Real Estate Construction [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 12.2 | 0.0 |
Financing Receivables, 30 to 59 Days Past Due | Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 16.2 | 2.2 |
Financing Receivables, 30 to 59 Days Past Due | Residential Mortgage [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 4.7 | 3.8 |
Financing Receivables, 30 to 59 Days Past Due | Agricultural Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 2.0 | 0.8 |
Financing Receivables, 30 to 59 Days Past Due | Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 30.5 | 12.3 |
Financing Receivables, 30 to 59 Days Past Due | Indirect consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 6.4 | 7.6 |
Financing Receivables, 30 to 59 Days Past Due | Other consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.8 | 1.2 |
Financing Receivables, 30 to 59 Days Past Due | Credit card consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.6 | 0.8 |
Financing Receivables, 30 to 59 Days Past Due | Total consumer loans |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 7.8 | 9.6 |
Financing Receivables, 30 to 59 Days Past Due | Commercial Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 6.2 | 4.8 |
Financing Receivables, 30 to 59 Days Past Due | Other, including overdrafts |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, 30 to 59 Days Past Due | Loans held for investment |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 44.9 | 27.6 |
Financing Receivables, 30 to 59 Days Past Due | Agricultural Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.4 | 0.9 |
Financing Receivables, 60 to 89 Days Past Due | Commercial Real Estate Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.2 | 1.1 |
Financing Receivables, 60 to 89 Days Past Due | Land Acquisition And Development Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.1 | 0.8 |
Financing Receivables, 60 to 89 Days Past Due | Residential Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.4 | 0.8 |
Financing Receivables, 60 to 89 Days Past Due | Commercial Real Estate Construction [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, 60 to 89 Days Past Due | Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.5 | 1.6 |
Financing Receivables, 60 to 89 Days Past Due | Residential Mortgage [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.6 | 1.4 |
Financing Receivables, 60 to 89 Days Past Due | Agricultural Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.5 |
Financing Receivables, 60 to 89 Days Past Due | Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 4.3 | 4.6 |
Financing Receivables, 60 to 89 Days Past Due | Indirect consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 2.0 | 1.9 |
Financing Receivables, 60 to 89 Days Past Due | Other consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.2 | 0.5 |
Financing Receivables, 60 to 89 Days Past Due | Credit card consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.4 | 0.5 |
Financing Receivables, 60 to 89 Days Past Due | Total consumer loans |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 2.6 | 2.9 |
Financing Receivables, 60 to 89 Days Past Due | Commercial Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.8 | 2.6 |
Financing Receivables, 60 to 89 Days Past Due | Other, including overdrafts |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, 60 to 89 Days Past Due | Loans held for investment |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 9.3 | 10.2 |
Financing Receivables, 60 to 89 Days Past Due | Agricultural Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.6 | 0.1 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial Real Estate Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 4.0 | 0.6 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Land Acquisition And Development Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.1 | 0.3 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Residential Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial Real Estate Construction [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Real Estate Construction Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.1 | 0.3 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Residential Mortgage [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.5 | 1.1 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Agricultural Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Real Estate Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 4.6 | 2.0 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Indirect consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.5 | 0.5 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Other consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.2 | 0.1 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Credit card consumer |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.6 | 0.8 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Total consumer loans |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.3 | 1.4 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial Portfolio Segment [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 1.2 | 2.3 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Other, including overdrafts |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 0.0 | 0.0 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Loans held for investment |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | 8.5 | 5.7 |
Financing Receivables, Equal to Greater than 90 Days Past Due | Agricultural Financing Receivable [Member] |  |  |
Loans and Leases Receivable Recorded Investment, Past Due |  |  |
Total Loans 30 or More Days Past Due | $ 1.4 | $ 0.0 |

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