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SECURITIES - Securities Available for Sale (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Amortized cost and estimated fair value of securities available for sale [Abstract] |  |  |  |  |
Amortized Cost | $ 384,547,000 |  | $ 384,547,000 |  | $ 282,256,000
Unrealized Gains | 12,062,000 |  | 12,062,000 |  | 3,146,000
Unrealized Losses | 309,000 |  | 309,000 |  | 1,312,000
Estimated Fair Value | 396,300,000 |  | 396,300,000 |  | 284,090,000
Amortized Cost [Abstract] |  |  |  |  |
Within one year | 0 |  | 0 |  |
After one, but within five years | 27,232,000 |  | 27,232,000 |  |
After five, but within ten years | 19,703,000 |  | 19,703,000 |  |
After ten years | 759,000 |  | 759,000 |  |
Total | 47,694,000 |  | 47,694,000 |  |
Amortized Cost | 384,547,000 |  | 384,547,000 |  | 282,256,000
Fair Value [Abstract] |  |  |  |  |
Within one year | 0 |  | 0 |  |
After one, but within five years | 28,769,000 |  | 28,769,000 |  |
After five, but within ten years | 20,755,000 |  | 20,755,000 |  |
After ten years | 800,000 |  | 800,000 |  |
Total | 50,324,000 |  | 50,324,000 |  |
Estimated Fair Value | 396,300,000 |  | 396,300,000 |  | 284,090,000
Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract] |  |  |  |  |
Proceeds form sale of securities resulting in gain (loss) | 0 | $ 0 | 0 | $ 15,200,000 |
Debt Securities, Available-for-sale, Realized Gain |  |  | 0 | 79,000 |
Debt Securities, Available-for-sale, Realized Loss |  |  | 0 | (60,000) |
Tax Expense from the Sale of Available-for-Sale Securities |  |  | 0 | $ 5,000 |
Mortgage-backed securities, residential |  |  |  |  |
Amortized cost and estimated fair value of securities available for sale [Abstract] |  |  |  |  |
Amortized Cost | 317,087,000 |  | 317,087,000 |  | 225,029,000
Unrealized Gains | 9,385,000 |  | 9,385,000 |  | 1,471,000
Unrealized Losses | 204,000 |  | 204,000 |  | 1,266,000
Estimated Fair Value | 326,268,000 |  | 326,268,000 |  | 225,234,000
Amortized Cost [Abstract] |  |  |  |  |
Without single maturity date | 317,087,000 |  | 317,087,000 |  |
Amortized Cost | 317,087,000 |  | 317,087,000 |  | 225,029,000
Fair Value [Abstract] |  |  |  |  |
Without single maturity date | 326,268,000 |  | 326,268,000 |  |
Estimated Fair Value | 326,268,000 |  | 326,268,000 |  | 225,234,000
Obligations of states and political subdivisions |  |  |  |  |
Amortized cost and estimated fair value of securities available for sale [Abstract] |  |  |  |  |
Amortized Cost | 40,694,000 |  | 40,694,000 |  | 41,265,000
Unrealized Gains | 2,566,000 |  | 2,566,000 |  | 1,580,000
Unrealized Losses | 0 |  | 0 |  | 0
Estimated Fair Value | 43,260,000 |  | 43,260,000 |  | 42,845,000
Amortized Cost [Abstract] |  |  |  |  |
Amortized Cost | 40,694,000 |  | 40,694,000 |  | 41,265,000
Fair Value [Abstract] |  |  |  |  |
Estimated Fair Value | 43,260,000 |  | 43,260,000 |  | 42,845,000
Corporate bonds and notes |  |  |  |  |
Amortized cost and estimated fair value of securities available for sale [Abstract] |  |  |  |  |
Amortized Cost | 7,000,000 |  | 7,000,000 |  | 250,000
Unrealized Gains | 64,000 |  | 64,000 |  | 0
Unrealized Losses | 0 |  | 0 |  | 0
Estimated Fair Value | 7,064,000 |  | 7,064,000 |  | 250,000
Amortized Cost [Abstract] |  |  |  |  |
Amortized Cost | 7,000,000 |  | 7,000,000 |  | 250,000
Fair Value [Abstract] |  |  |  |  |
Estimated Fair Value | 7,064,000 |  | 7,064,000 |  | 250,000
SBA loan pools |  |  |  |  |
Amortized cost and estimated fair value of securities available for sale [Abstract] |  |  |  |  |
Amortized Cost | 19,766,000 |  | 19,766,000 |  | 15,712,000
Unrealized Gains | 47,000 |  | 47,000 |  | 95,000
Unrealized Losses | 105,000 |  | 105,000 |  | 46,000
Estimated Fair Value | 19,708,000 |  | 19,708,000 |  | 15,761,000
Amortized Cost [Abstract] |  |  |  |  |
Without single maturity date | 19,766,000 |  | 19,766,000 |  |
Amortized Cost | 19,766,000 |  | 19,766,000 |  | 15,712,000
Fair Value [Abstract] |  |  |  |  |
Without single maturity date | 19,708,000 |  | 19,708,000 |  |
Estimated Fair Value | $ 19,708,000 |  | $ 19,708,000 |  | $ 15,761,000

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