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Fair Value Measurements and Fair Value of Financial Instruments, Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Financial assets [Abstract] |  |
HTM securities | $ 632,954 | $ 636,827
Carrying Amount [Member] | Level 1 [Member] |  |
Financial liabilities [Abstract] |  |
Subordinated debt | 100,000 | 100,000
Carrying Amount [Member] | Level 2 [Member] |  |
Financial assets [Abstract] |  |
HTM securities | 622,351 | 616,560
Financial liabilities [Abstract] |  |
Time deposits | 569,029 | 633,479
Long-term debt | 14,045 | 39,097
Junior subordinated debt | 101,196 | 101,196
Carrying Amount [Member] | Level 3 [Member] |  |
Financial assets [Abstract] |  |
Net loans | 7,420,531 | 7,390,004
Estimated Fair Value [Member] | Level 1 [Member] |  |
Financial liabilities [Abstract] |  |
Subordinated debt | 108,671 | 103,277
Estimated Fair Value [Member] | Level 2 [Member] |  |
Financial assets [Abstract] |  |
HTM securities | 632,954 | 636,827
Financial liabilities [Abstract] |  |
Time deposits | 606,134 | 638,721
Long-term debt | 14,545 | 39,820
Junior subordinated debt | 109,940 | 108,926
Estimated Fair Value [Member] | Level 3 [Member] |  |
Financial assets [Abstract] |  |
Net loans | $ 7,525,470 | $ 7,530,033

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