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SUMMARY OF ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands | 3 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2021 | Jan. 01, 2021 | Dec. 31, 2020 | Mar. 31, 2020 | Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Allowance for credit losses | $ 98,200 |  | $ 41,461 | $ 36,463 | $ 28,441
Retained earnings | $ 574,297 |  | 600,641 |  |
Acquisition, Development, And Construction Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Value ratio | 50.00% |  |  |  |
Small Business Administration ("SBA") Paycheck Protection Program ("PPP") |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Value ratio | 100.00% |  |  |  |
Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Allowance for credit losses |  |  | $ (3,919) |  |
Maximum [Member] | One-to-four family residential and cooperative/condominium apartment |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Value ratio | 75.00% |  |  |  |
Maximum [Member] | Multifamily residential and residential mixed-use |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Value ratio | 75.00% |  |  |  |
Maximum [Member] | Commercial real estate ("CRE") |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Value ratio | 75.00% |  |  |  |
Minimum [Member] | One-to-four family residential and cooperative/condominium apartment |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Debt service ratio | 1.25% |  |  |  |
Minimum [Member] | Multifamily residential and residential mixed-use |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Debt service ratio | 1.20% |  |  |  |
Minimum [Member] | Commercial real estate ("CRE") |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Debt service ratio | 1.25% |  |  |  |
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Allowance for credit losses | $ (3,900) |  |  |  |
Reserve for unfunded commitments | $ 1,400 |  |  |  |
Retained earnings |  | $ 1,700 |  |  |

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