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SECURITIES - Securities Held to Maturity (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
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Amortized cost and estimated fair value of securities held to maturity [Abstract] |  |
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017 | $ 3,861 | $ 4,875
Unrealized Gains | 0 | 0
Unrealized Losses | 4 | 17
Securities held to maturity | 3,857 | 4,858
Amortized Cost [Abstract] |  |
Within one year | 1,866 |
After one, but within five years | 1,995 |
After five, but within ten years | 0 |
After ten years | 0 |
Total | 3,861 |
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017 | 3,861 | 4,875
Fair Value [Abstract] |  |
Within one year | 1,863 |
After one, but within five years | 1,994 |
After five, but within ten years | 0 |
After ten years | 0 |
Total | 3,857 |
Securities held to maturity | 3,857 | 4,858
Obligations of states and political subdivisions |  |
Amortized cost and estimated fair value of securities held to maturity [Abstract] |  |
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017 | 2,006 | 3,020
Unrealized Gains | 0 | 0
Unrealized Losses | 0 | 0
Securities held to maturity | 2,006 | 3,020
Amortized Cost [Abstract] |  |
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017 | 2,006 | 3,020
Fair Value [Abstract] |  |
Securities held to maturity | 2,006 | 3,020
Time deposits with other financial institutions |  |
Amortized cost and estimated fair value of securities held to maturity [Abstract] |  |
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017 | 1,855 | 1,855
Unrealized Gains | 0 | 0
Unrealized Losses | 4 | 17
Securities held to maturity | 1,851 | 1,838
Amortized Cost [Abstract] |  |
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017 | 1,855 | 1,855
Fair Value [Abstract] |  |
Securities held to maturity | 1,851 | $ 1,838
Mortgage-backed securities, residential |  |
Amortized Cost [Abstract] |  |
Without single maturity date | 0 |
SBA loan pools |  |
Amortized Cost [Abstract] |  |
Without single maturity date | $ 0 |

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