LOANS - Summary of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 5,297,283	$ 4,794,759
Premiums, discounts and deferred fees and expenses	11,676	9,040
Total	5,308,959	4,803,799
Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total loans		3,053,556
Total	3,349,199
Multifamily
Accounts Notes And Loans Receivable [Line Items]
Total	2,527,964
Single family
Accounts Notes And Loans Receivable [Line Items]
Total	821,235
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans		747,807
Total	670,326
Land and Construction
Accounts Notes And Loans Receivable [Line Items]
Total loans		55,832
Total	63,701
Commercial and Industrial Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	1,217,078	918,676
Total	1,216,241
Consumer Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	9,468	18,888
Total	9,492
Real Estate Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	4,070,737	3,857,195
Real Estate Loans \| Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,337,119	3,053,556
Total	3,349,199
Real Estate Loans \| Multifamily
Accounts Notes And Loans Receivable [Line Items]
Total loans	2,518,151	2,247,542
Real Estate Loans \| Single family
Accounts Notes And Loans Receivable [Line Items]
Total loans	818,968	806,014
Real Estate Loans \| Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans	669,912	747,807
Total	670,326
Real Estate Loans \| Land and Construction
Accounts Notes And Loans Receivable [Line Items]
Total loans	63,706	$ 55,832
Total	$ 63,701

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Amount of unamortized loan commitment, origination, and other fees (costs) and purchase premium (discount) on financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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