FAIR VALUE OF ASSETS AND LIABILITIES - Summary of assets and liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	$ 314,146	$ 244,587
U.S. Treasury Note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	6,773	10,000
Domestic Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	88,118	59,341
U.S. Government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	25,240	19,675
Obligations issued by U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	22,264	24,795
Residential one-to-four family
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	122,803	72,716
Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	42,214	58,060
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	6,734
Measured on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets	314,146	244,587
Financial Liabilities	(1,520)	(5,545)
Measured on a recurring basis: | U.S. Treasury Note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	6,773	10,000
Measured on a recurring basis: | Domestic Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	88,118	59,341
Measured on a recurring basis: | U.S. Government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	25,240	19,675
Measured on a recurring basis: | Obligations issued by U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	22,264	24,795
Measured on a recurring basis: | Residential one-to-four family
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	122,803	72,716
Measured on a recurring basis: | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	42,214	58,060
Measured on a recurring basis: | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	6,734
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets	26,091	22,417
Financial Liabilities	0	0
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | U.S. Treasury Note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	6,773	10,000
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | Domestic Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | U.S. Government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	19,318	12,417
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | Obligations issued by U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | Residential one-to-four family
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0
Measured on a recurring basis: | Significant Other Observable Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets	288,055	222,170
Financial Liabilities	(1,520)	(5,545)
Measured on a recurring basis: | Significant Other Observable Inputs | U.S. Treasury Note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Other Observable Inputs | Domestic Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	88,118	59,341
Measured on a recurring basis: | Significant Other Observable Inputs | U.S. Government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	5,922	7,258
Measured on a recurring basis: | Significant Other Observable Inputs | Obligations issued by U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	22,264	24,795
Measured on a recurring basis: | Significant Other Observable Inputs | Residential one-to-four family
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	122,803	72,716
Measured on a recurring basis: | Significant Other Observable Inputs | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	42,214	58,060
Measured on a recurring basis: | Significant Other Observable Inputs | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	6,734
Measured on a recurring basis: | Significant Unobservable Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets	0	0
Financial Liabilities	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | U.S. Treasury Note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | Domestic Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | U.S. Government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | Obligations issued by U.S. states and their political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | Residential one-to-four family
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0	0
Measured on a recurring basis: | Significant Unobservable Inputs | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale:	0
Measured on a nonrecurring basis: | Assets held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	5,225	5,295
Measured on a nonrecurring basis: | Real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	624	624
Measured on a nonrecurring basis: | Quoted Prices in Active Markets for Identical Assets | Assets held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	0	0
Measured on a nonrecurring basis: | Quoted Prices in Active Markets for Identical Assets | Real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	0	0
Measured on a nonrecurring basis: | Significant Other Observable Inputs | Assets held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	5,225	5,295
Measured on a nonrecurring basis: | Significant Other Observable Inputs | Real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	624	624
Measured on a nonrecurring basis: | Significant Unobservable Inputs | Assets held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	0	0
Measured on a nonrecurring basis: | Significant Unobservable Inputs | Real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonfinancial assets	$ 0	$ 0