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SUMMARY OF ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands | 9 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Sep. 30, 2021 | Jun. 30, 2021 | Jan. 01, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses | $ 81,255 | $ 92,760 |  | $ 41,461 | $ 48,492 | $ 42,492 | $ 28,441
Retained earnings | 630,744 |  |  | 600,641 |  |  |
Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  | (3,919) |  |  |
Accounting Standards Update 2016-13 | 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 |  |  |  |
One-to-four family residential and cooperative/condominium apartment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses | $ 6,104 | 5,522 |  | 644 | 799 | 671 | 269
One-to-four family residential and cooperative/condominium apartment | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  | 1,048 |  |  |
One-to-four family residential and cooperative/condominium apartment | Maximum |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Value ratio | 75.00% |  |  |  |  |  |
One-to-four family residential and cooperative/condominium apartment | Minimum |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Debt service ratio | 1.25% |  |  |  |  |  |
Multifamily residential and residential mixed-use |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses | $ 8,307 | 10,285 |  | 17,016 | 20,210 | 16,666 | 10,142
Multifamily residential and residential mixed-use | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  | (8,254) |  |  |
Multifamily residential and residential mixed-use | Maximum |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Value ratio | 75.00% |  |  |  |  |  |
Multifamily residential and residential mixed-use | Minimum |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Debt service ratio | 1.20% |  |  |  |  |  |
Commercial real estate ("CRE") |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses | $ 29,603 | 41,201 |  | 9,059 | 12,021 | 9,859 | 3,900
Commercial real estate ("CRE") | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  | 4,849 |  |  |
Commercial real estate ("CRE") | Maximum |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Value ratio | 75.00% |  |  |  |  |  |
Commercial real estate ("CRE") | Minimum |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Debt service ratio | 1.25% |  |  |  |  |  |
Acquisition, Development, And Construction Loans |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Value ratio | 50.00% |  |  |  |  |  |
Commercial and Industrial ("C&I") Loans |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses | $ 31,545 | 30,095 |  | 12,737 | 13,395 | 13,502 | 12,870
Value ratio | 100.00% |  |  |  |  |  |
Commercial and Industrial ("C&I") Loans | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  | (1,935) |  |  |
Other Loans |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses | $ 677 | $ 499 |  | 12 | $ 16 | $ 17 | $ 16
Other Loans | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  | $ (8) |  |  |

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