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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) |  | 9 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 16, 2020 | Sep. 30, 2021 USD ($) Subsidary Family ResidentialHouse | Sep. 30, 2020 USD ($) | Dec. 31, 2020 USD ($) | Mar. 27, 2020 USD ($)
Property, Plant and Equipment [Line Items] |  |  |  |  |
Number of subsidiaries | Subsidary |  | 6 |  |  |
Decrease to retained earnings |  | $ 100,910,000 |  | $ 113,449,000 |
Retained earnings, net of tax |  |  | $ 955,000 |  |
Number of families secured by loans of real estate | Family |  | 4 |  |  |
Number of housing units secured by loans from segment | ResidentialHouse |  | 5 |  |  |
Paycheck Protection Program Loans |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Percentage of government guaranteed loans |  | 100.00% |  |  |
COVID-19 |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Maximum authorized amount of coronavirus aid, relief and economic security |  |  |  |  | $ 2,000,000,000,000
Description of federal fund interest rate |  | Due to the COVID-19 pandemic, market interest rates declined significantly, with the 10-year Treasury bond falling below 1.00% on March 3, 2020 for the first time. On March 16, 2020, the Federal Open Market Committee reduced the target federal funds rate range to 0.00% to 0.25%, at which it remains as of September 30, 2021. |  |  |
COVID-19 | Minimum |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Federal open market committee reduced target federal funds interest rate. | 0.00% |  |  |  |
COVID-19 | Maximum |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Federal open market committee reduced target federal funds interest rate. | 0.25% |  |  |  |

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