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Acquisitions - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions | Apr. 08, 2019 | Mar. 31, 2020 | Dec. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | --- | --- | --- | ---
Liabilities assumed: |  |  |  |  |  |
Goodwill |  | $ 621.6 | $ 621.6 | $ 621.6 | $ 621.6 | $ 546.7
Idaho Independent Bank, As Recorded By Idaho Independent Bank |  |  |  |  |  |
Assets acquired: |  |  |  |  |  |
Mortgage loans held for sale | $ 0.5 |  |  |  |  |
Allowance for loan loss | (6.3) |  |  |  |  |
Premises and equipment | 16.5 |  |  |  |  |
Other real estate owned (“OREO”) | 0.4 |  |  |  |  |
Company owned life insurance | 15.2 |  |  |  |  |
Core deposit intangible assets | 0.0 |  |  |  |  |
Deferred tax assets, net | 3.2 |  |  |  |  |
Other assets | 8.6 |  |  |  |  |
Total assets acquired | 719.1 |  |  |  |  |
Liabilities assumed: |  |  |  |  |  |
Deposits | 596.5 |  |  |  |  |
Accounts payable and accrued expense | 15.2 |  |  |  |  |
Other borrowed funds | 4.0 |  |  |  |  |
Securities sold under repurchase agreements | 30.4 |  |  |  |  |
Total liabilities assumed | 646.1 |  |  |  |  |
Net assets acquired | 73.0 |  |  |  |  |
Idaho Independent Bank, Fair Value Adjustments |  |  |  |  |  |
Assets acquired: |  |  |  |  |  |
Cash and cash equivalents | 0.0 |  |  |  |  |
Investment securities | 0.5 |  |  |  |  |
Loans held for investment | (9.8) |  |  |  |  |
Mortgage loans held for sale | 0.0 |  |  |  |  |
Allowance for loan loss | 6.3 |  |  |  |  |
Premises and equipment | 4.8 |  |  |  |  |
Other real estate owned (“OREO”) | 2.0 |  |  |  |  |
Company owned life insurance | 0.0 |  |  |  |  |
Core deposit intangible assets | 13.6 |  |  |  |  |
Deferred tax assets, net | (2.6) |  |  |  |  |
Other assets | (0.7) |  |  |  |  |
Total assets acquired | 14.1 |  |  |  |  |
Liabilities assumed: |  |  |  |  |  |
Deposits | 0.1 |  |  |  |  |
Accounts payable and accrued expense | 2.6 |  |  |  |  |
Other borrowed funds | 0.1 |  |  |  |  |
Securities sold under repurchase agreements | 0.0 |  |  |  |  |
Total liabilities assumed | 2.8 |  |  |  |  |
Net assets acquired | 11.3 |  |  |  |  |
Idaho Independent Bank |  |  |  |  |  |
Assets acquired: |  |  |  |  |  |
Cash and cash equivalents | 270.7 |  |  |  |  |
Investment securities | 63.2 |  |  |  |  |
Loans held for investment | 337.8 |  |  |  |  |
Mortgage loans held for sale | 0.5 |  |  |  |  |
Allowance for loan loss | 0.0 |  |  |  |  |
Premises and equipment | 21.3 |  |  |  |  |
Other real estate owned (“OREO”) | 2.4 |  |  |  |  |
Company owned life insurance | 15.2 |  |  |  |  |
Core deposit intangible assets | 13.6 |  |  |  |  |
Deferred tax assets, net | 0.6 |  |  |  |  |
Other assets | 7.9 |  |  |  |  |
Total assets acquired | 733.2 |  |  |  |  |
Liabilities assumed: |  |  |  |  |  |
Deposits | 596.6 |  |  |  |  |
Accounts payable and accrued expense | 17.8 |  |  |  |  |
Other borrowed funds | 4.1 |  |  |  |  |
Securities sold under repurchase agreements | 30.4 |  |  |  |  |
Total liabilities assumed | 648.9 |  |  |  |  |
Net assets acquired | 84.3 |  |  |  |  |
Class A common stock | 157.3 |  |  |  |  |
Total consideration paid | 157.3 |  |  |  |  |
Goodwill | 73.0 |  |  |  |  |
Northwest Bank Acquisition, As Recorded By Inland Northwest Bank |  |  |  |  |  |
Assets acquired: |  |  |  |  |  |
Cash and cash equivalents | 270.7 |  |  |  |  |
Investment securities | 62.7 |  |  |  |  |
Loans held for investment | $ 347.6 |  |  |  |  |

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