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SUBORDINATED DEBENTURES - Narrative (Details) - USD ($) | 1 Months Ended | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
May 31, 2020 | Dec. 31, 2019 | Jul. 31, 2019 | Jul. 31, 2018 | May 31, 2017 | Jun. 30, 2020 | Sep. 30, 2020 | Dec. 31, 2015
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Liquidation value per share |  |  |  |  |  |  | $ 1,000 |
Debentures mature date |  |  |  |  |  |  | 30 years |
Subordinated debentures | Trust II Debentures |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debenture issued |  |  |  |  |  |  | $ 3,093,000 |
Subordinated debentures | Trust II Debentures | Minimum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures |  |  |  |  |  |  | 30 days |
Subordinated debentures | Trust II Debentures | Maximum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures |  |  |  |  |  |  | 60 days |
Redemption price of debentures as a percentage of principal |  |  |  |  |  |  | 100.00% |
Subordinated debentures | Trust II Debentures | 3 Month LIBOR |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Spread on variable rate |  |  |  |  |  |  | 3.35% |
Subordinated debentures | Trust III Debentures |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debenture issued |  |  |  |  |  |  | $ 2,062,000 |
Subordinated debentures | Trust III Debentures | Minimum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures |  |  |  |  |  |  | 30 days |
Subordinated debentures | Trust III Debentures | Maximum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures |  |  |  |  |  |  | 60 days |
Redemption price of debentures as a percentage of principal |  |  |  |  |  |  | 100.00% |
Subordinated debentures | Trust III Debentures | 3 Month LIBOR |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Spread on variable rate |  |  |  |  |  |  | 1.67% |
Subordinated debentures | DCB Trust I Debentures |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debenture issued |  |  |  |  |  |  | $ 5,155,000 |
Subordinated debentures | DCB Trust I Debentures | Minimum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures |  |  |  |  |  |  | 30 days |
Subordinated debentures | DCB Trust I Debentures | Maximum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures |  |  |  |  |  |  | 60 days |
Redemption price of debentures as a percentage of principal |  |  |  |  |  |  | 100.00% |
Subordinated debentures | DCB Trust I Debentures | 3 Month LIBOR |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Spread on variable rate |  |  |  |  |  |  | 1.80% |
Subordinated debentures | Other Debentures Issued in December 2015 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Notice period required for redemption of debentures | 30 days |  |  |  |  |  |  |
Redemption price of debentures as a percentage of principal | 100.00% |  |  |  |  |  |  |
Debenture issued |  |  |  |  |  |  |  | $ 5,000,000
Debenture issued, par value per instrument issued | $ 500,000 |  |  |  |  |  |  |
Debt instrument maturity start date | Nov. 01, 2020 |  |  |  |  |  |  |
Debt instrument maturity end date | Nov. 01, 2024 |  |  |  |  |  |  |
Repayments of related party debt |  |  |  |  | $ 2,000,000 |  |  |
Subordinated debentures | Other Debentures Issued in December 2015 | Directors and Related Parties |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debenture issued | $ 10,000,000 |  |  |  |  |  |  | $ 2,500,000
Subordinated debentures | Other Debentures Issued in December 2015 | Minimum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Stated interest rate | 1.00% |  |  |  |  |  |  |
Subordinated debentures | Other Debentures Issued in December 2015 | Maximum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Stated interest rate | 4.00% |  |  |  |  |  |  |
Subordinated debentures | Other Debentures Issued in July 2015 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debentures that matured and were paid off |  | $ 500,000 | $ 1,000,000 | $ 1,000,000 |  | $ 500,000 |  |

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