LOANS, Loan Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Loans [Abstract]
Total Loans	$ 5,444,382	$ 5,340,538
Allowance for loan losses	(42,492)	(28,441)
Total loans, net	5,401,890	5,312,097
Real Estate Loans [Member]
Loans [Abstract]
Total Loans	4,811,401	5,002,354
Real Estate Loans [Member] \| One- to-Four Family Residential, Including Condominium and Cooperative Apartment [Member]
Loans [Abstract]
Total Loans	182,264	148,429
Real Estate Loans [Member] \| Multifamily Residential and Residential Mixed-Use [Member]
Loans [Abstract]
Total Loans	2,988,511	3,385,375
Real Estate Loans [Member] \| Commercial Real Estate and Commercial Mixed-Use [Member]
Loans [Abstract]
Total Loans	1,504,020	1,350,185
Real Estate Loans [Member] \| Acquisition, Development, and Construction ("ADC") [Member]
Loans [Abstract]
Total Loans	136,606	118,365
Commercial and Industrial ("C&I") Loans [Member]
Loans [Abstract]
Total Loans	631,518	336,412
Commercial and Industrial ("C&I") Loans [Member] \| Small Business Administration ("SBA") Paycheck Protection Program ("PPP") [Member]
Loans [Abstract]
Total Loans	310,509
Other Loans [Member]
Loans [Abstract]
Total Loans	$ 1,463	$ 1,772

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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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 after allowance and 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 and loans held for sale.

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