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Loans - Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | $ 76.4 |  | $ 76.4 |  | $ 83.0
Recorded Investment With No Allowance | 27.3 |  | 27.3 |  | 36.0
Recorded Investment With Allowance | 29.6 |  | 29.6 |  | 28.8
Total Recorded Investment | 56.9 |  | 56.9 |  | 64.8
Related Allowance | 6.2 |  | 6.2 |  | 6.8
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income |  |  |  |  |
Average Recorded Investment | 59.3 | $ 79.0 | 60.9 | $ 82.5 |
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract] |  |  |  |  |
Income Recognized | 0.1 | 0.2 | 0.1 | 0.2 |
Commercial |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 24.9 |  | 24.9 |  | 22.2
Recorded Investment With No Allowance | 11.6 |  | 11.6 |  | 8.6
Recorded Investment With Allowance | 7.6 |  | 7.6 |  | 7.7
Total Recorded Investment | 19.2 |  | 19.2 |  | 16.3
Related Allowance | 0.9 |  | 0.9 |  | 0.7
Land acquisition & development |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 6.7 |  | 6.7 |  | 10.0
Recorded Investment With No Allowance | 0.4 |  | 0.4 |  | 0.4
Recorded Investment With Allowance | 0.1 |  | 0.1 |  | 3.5
Total Recorded Investment | 0.5 |  | 0.5 |  | 3.9
Related Allowance | 0.0 |  | 0.0 |  | 0.2
Residential |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 1.5 |  | 1.5 |  | 1.1
Recorded Investment With No Allowance | 1.3 |  | 1.3 |  | 0.6
Recorded Investment With Allowance | 0.0 |  | 0.0 |  | 0.4
Total Recorded Investment | 1.3 |  | 1.3 |  | 1.0
Related Allowance | 0.0 |  | 0.0 |  | 0.1
Commercial |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 0.6 |  | 0.6 |  | 0.7
Recorded Investment With No Allowance | 0.1 |  | 0.1 |  | 0.2
Recorded Investment With Allowance | 0.1 |  | 0.1 |  | 0.0
Total Recorded Investment | 0.2 |  | 0.2 |  | 0.2
Related Allowance | 0.0 |  | 0.0 |  | 0.0
Total construction loans |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 8.8 |  | 8.8 |  | 11.8
Recorded Investment With No Allowance | 1.8 |  | 1.8 |  | 1.2
Recorded Investment With Allowance | 0.2 |  | 0.2 |  | 3.9
Total Recorded Investment | 2.0 |  | 2.0 |  | 5.1
Related Allowance | 0.0 |  | 0.0 |  | 0.3
Residential |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 6.6 |  | 6.6 |  | 8.8
Recorded Investment With No Allowance | 3.3 |  | 3.3 |  | 5.7
Recorded Investment With Allowance | 2.0 |  | 2.0 |  | 2.0
Total Recorded Investment | 5.3 |  | 5.3 |  | 7.7
Related Allowance | 0.3 |  | 0.3 |  | 0.3
Agricultural |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 4.8 |  | 4.8 |  | 12.9
Recorded Investment With No Allowance | 2.7 |  | 2.7 |  | 12.5
Recorded Investment With Allowance | 1.7 |  | 1.7 |  | 0.2
Total Recorded Investment | 4.4 |  | 4.4 |  | 12.7
Related Allowance | 0.1 |  | 0.1 |  | 0.0
Total real estate loans |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 45.1 |  | 45.1 |  | 55.7
Recorded Investment With No Allowance | 19.4 |  | 19.4 |  | 28.0
Recorded Investment With Allowance | 11.5 |  | 11.5 |  | 13.8
Total Recorded Investment | 30.9 |  | 30.9 |  | 41.8
Related Allowance | 1.3 |  | 1.3 |  | 1.3
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income |  |  |  |  |
Average Recorded Investment | 33.9 | 56.4 | 36.4 | 58.6 |
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract] |  |  |  |  |
Income Recognized | 0.0 | 0.1 | 0.0 | 0.1 |
Commercial |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 24.3 |  | 24.3 |  | 24.1
Recorded Investment With No Allowance | 6.2 |  | 6.2 |  | 5.5
Recorded Investment With Allowance | 13.1 |  | 13.1 |  | 14.4
Total Recorded Investment | 19.3 |  | 19.3 |  | 19.9
Related Allowance | 4.6 |  | 4.6 |  | 5.2
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income |  |  |  |  |
Average Recorded Investment | 19.6 | 20.7 | 19.6 | 22.5 |
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract] |  |  |  |  |
Income Recognized | 0.1 | 0.1 | 0.1 | 0.1 |
Agricultural |  |  |  |  |
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid Total Principal Balance | 7.0 |  | 7.0 |  | 3.2
Recorded Investment With No Allowance | 1.7 |  | 1.7 |  | 2.5
Recorded Investment With Allowance | 5.0 |  | 5.0 |  | 0.6
Total Recorded Investment | 6.7 |  | 6.7 |  | 3.1
Related Allowance | 0.3 |  | 0.3 |  | $ 0.3
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income |  |  |  |  |
Average Recorded Investment | 5.8 | 1.9 | 4.9 | 1.4 |
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract] |  |  |  |  |
Income Recognized | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 |

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