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MARKETABLE SECURITIES - Narrative (Details) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 USD ($) Position Security | Sep. 30, 2020 Security | Sep. 30, 2021 USD ($) Security Position | Sep. 30, 2020 Security | Dec. 31, 2020 USD ($)
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] |  |  |  |  |
Allowance for credit losses for available for sale debt securities | $ 0 |  | $ 0 |  | $ 0
Number of investment in an unrealized loss position | Position | 26 |  | 26 |  |
Number of investment in an sale debt securities | Position | 22 |  | 22 |  |
Percentage of unrealized loss exceeds book value |  |  | 20.00% |  |
Number of securities other than agencies amount | Security |  |  | 0 |  |
Fair value of securities pledged as collateral | $ 279,726,000 |  | $ 279,726,000 |  | $ 314,962,000
Number of securities sold | Security | 0 | 0 | 0 | 0 |
Unamortized, unrealized gain remaining on transferred securities |  |  | $ 9,684,000 |  |

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