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Employee Benefit Plans (Present Value of Accrued Liability) (Details) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | May 01, 2019 | Apr. 02, 2019
Present Value Of Accrued Liability [Roll Forward] |  |  |  |  |
Discount rate adjustment | $ 1,719 | $ 1,574 |  |  |
Benefit expense and interest cost | 8,111 | (1,582) | $ 4,572 |  |
Interest cost | $ 34,197 | $ 37,260 | 34,733 |  |
Discount rate | 2.76% | 3.46% |  |  |
Executives Directors And Officer Of Acquired Entities |  |  |  |  |
Present Value Of Accrued Liability [Roll Forward] |  |  |  |  |
Present value of accrued liability as of January 1 | $ 45,295 | $ 34,063 |  |  |
Benefit expense and interest cost | 3,503 | 2,396 |  |  |
Benefits paid | 7,862 | 4,681 |  |  |
Present value of accrued liability as of December 31 | 42,655 | 45,295 | $ 34,063 |  |
Biscayne Bancshares |  |  |  |  |
Present Value Of Accrued Liability [Roll Forward] |  |  |  |  |
Liability assumed | 0 | 1,138 |  |  | $ 956,800
First South Bancorp |  |  |  |  |
Present Value Of Accrued Liability [Roll Forward] |  |  |  |  |
Liability assumed | 0 | 1,067 |  | $ 215,600 |
Entegra |  |  |  |  |
Present Value Of Accrued Liability [Roll Forward] |  |  |  |  |
Liability assumed | $ 0 | $ 9,738 |  |  |

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