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FAIR VALUE - Summary of Assets and Liabilities measured on a Recurring Basis (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Assets measured at fair value on recurring basis |  |
Available for sale securities | $ 450,360 | $ 638,291
Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 450,360 | 638,291
Financial Assets: Derivatives | 49,662 | 15,437
Financial Liabilities: |  |
Financial liabilities: Derivatives | 56,417 | 16,645
Fair Value |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 450,360 | 638,291
Financial Assets: Derivatives | 49,662 | 15,437
Financial Liabilities: |  |
Financial liabilities: Derivatives | 56,417 | 16,645
U.S. Treasury securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities |  | 50,822
U.S. GSE securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities |  | 4,995
State and municipal obligations |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 42,088 | 34,964
U.S. GSE residential mortgage-backed securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 113,235 | 84,691
U.S. GSE residential collateralized mortgage obligations |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 128,804 | 277,851
U.S. GSE commercial mortgage-backed securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 24,807 | 13,609
U.S. GSE commercial collateralized mortgage obligations |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 62,336 | 104,156
Other asset backed securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 23,950 | 23,401
Corporate |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 55,140 | 43,802
Significant Other Observable Inputs (Level 2) |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 450,360 | 638,291
Financial Assets: Derivatives | 49,662 | 15,437
Financial Liabilities: |  |
Financial liabilities: Derivatives | 56,417 | 16,645
Recurring basis | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 450,360 | 638,291
Recurring basis | U.S. Treasury securities | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities |  | 50,822
Recurring basis | U.S. GSE securities | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities |  | 4,995
Recurring basis | State and municipal obligations | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 42,088 | 34,964
Recurring basis | U.S. GSE residential mortgage-backed securities | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 113,235 | 84,691
Recurring basis | U.S. GSE residential collateralized mortgage obligations | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 128,804 | 277,851
Recurring basis | U.S. GSE commercial mortgage-backed securities | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 24,807 | 13,609
Recurring basis | U.S. GSE commercial collateralized mortgage obligations | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 62,336 | 104,156
Recurring basis | Other asset backed securities | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 23,950 | 23,401
Recurring basis | Corporate | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 55,140 | 43,802
Recurring basis | Derivatives | Carrying Amount |  |
Assets measured at fair value on recurring basis |  |
Financial Assets: Derivatives | 49,662 | 15,437
Financial Liabilities: |  |
Financial liabilities: Derivatives | 56,417 | 16,645
Recurring basis | Significant Other Observable Inputs (Level 2) |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 450,360 | 638,291
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Treasury securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities |  | 50,822
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities |  | 4,995
Recurring basis | Significant Other Observable Inputs (Level 2) | State and municipal obligations |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 42,088 | 34,964
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE residential mortgage-backed securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 113,235 | 84,691
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE residential collateralized mortgage obligations |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 128,804 | 277,851
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE commercial mortgage-backed securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 24,807 | 13,609
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE commercial collateralized mortgage obligations |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 62,336 | 104,156
Recurring basis | Significant Other Observable Inputs (Level 2) | Other asset backed securities |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 23,950 | 23,401
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate |  |
Assets measured at fair value on recurring basis |  |
Available for sale securities | 55,140 | 43,802
Recurring basis | Significant Other Observable Inputs (Level 2) | Derivatives |  |
Assets measured at fair value on recurring basis |  |
Financial Assets: Derivatives | 49,662 | 15,437
Financial Liabilities: |  |
Financial liabilities: Derivatives | $ 56,417 | $ 16,645

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