SECURITIES - Summary of available for sale securities with unrealized losses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	$ (1,703)	$ (63)
Estimated Fair Value	135,064	7,525
Unrealized Losses	(144)	(148)
Estimated Fair Value	8,866	10,442
Unrealized Losses	(1,847)	(211)
Estimated Fair Value	143,930	17,967
U.S. Treasury Note
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	(128)	0
Estimated Fair Value	6,773	0
Unrealized Losses	0	0
Estimated Fair Value	0	0
Unrealized Losses	(128)	0
Estimated Fair Value	6,773	0
Corporate Bonds
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	(89)	0
Estimated Fair Value	17,415	0
Unrealized Losses	0	0
Estimated Fair Value	0	0
Unrealized Losses	(89)	0
Estimated Fair Value	17,415	0
U.S. Government agency obligations
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	0	(54)
Estimated Fair Value	0	3,559
Unrealized Losses	(144)	(147)
Estimated Fair Value	8,680	10,014
Unrealized Losses	(144)	(201)
Estimated Fair Value	8,680	13,573
Obligations issued by U.S. states and their political subdivisions
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	(3)	0
Estimated Fair Value	1,851	0
Unrealized Losses	0	0
Estimated Fair Value	0	0
Unrealized Losses	(3)	0
Estimated Fair Value	1,851	0
Residential one-to-four family
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	(1,364)	(7)
Estimated Fair Value	106,396	3,228
Unrealized Losses	0	(1)
Estimated Fair Value	0	115
Unrealized Losses	(1,364)	(8)
Estimated Fair Value	106,396	3,343
Multifamily
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	(73)	(2)
Estimated Fair Value	916	738
Unrealized Losses	0	0
Estimated Fair Value	186	313
Unrealized Losses	(73)	(2)
Estimated Fair Value	1,102	$ 1,051
Asset-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Unrealized Losses	(46)
Estimated Fair Value	1,713
Unrealized Losses	0
Estimated Fair Value	0
Unrealized Losses	(46)
Estimated Fair Value	$ 1,713

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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