LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES - Troubled debt restructured loans (Details) $ in Thousands	Sep. 30, 2023 USD ($) borrower loan	Dec. 31, 2022 USD ($)
Financing Receivable, Impaired [Line Items]
Troubled debt restructured loans	$ 8	$ 34
Non-accrual and 90+ days past due and still accruing loans to average loans	0.32%	0.25%
Allowance for credit losses to non-accrual and 90 days or more and still accruing loans	359.40%	433.90%
Single-family Residential
Financing Receivable, Impaired [Line Items]
Troubled debt restructured loans	$ 7,930
Number of loans | borrower	1
Commercial and Industrial | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Number of loans | loan	1