BASIS OF PRESENTATION (Details)		12 Months Ended
	Oct. 01, 2023 USD ($)	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Jan. 01, 2023 USD ($)	Jan. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)
Bankruptcy accounts subject to the licensing fees		$ 312,200,000	$ 425,300,000
Goodwill		9,700,000
Impairment of goodwill	$ 0		0
Investment in Disability Opportunity Fund		1,500,000	1,000,000.0
Investment in FRB		11,400,000	11,400,000
Investment in FHLB		25,600,000	9,200,000
Deposit with Federal Reserve Bank		236,400,000	226,700,000
Cash pledged as collateral		726,000	693,000
Escrow deposit		$ 11,500,000	13,300,000
Number of reportable operating segment | segment		1
Loan commitments		$ 57,965,000	44,876,000			$ 34,729,000
Retained earnings		$ 315,975,000	240,810,000
Cumulative Effect, Period of Adoption, Adjustment
Loan commitments			$ 2,250,000
Cumulative Effect, Period of Adoption, Adjustment | ASU 2016-02
Retained earnings					$ 0
Cumulative Effect, Period of Adoption, Adjustment | ASU 2016-13
Loan commitments				$ 3,000,000.0
Increased deferred tax assets				777,000
Retained earnings				$ 2,100,000
Minimum
Premises and equipment useful life		3 years
Maximum
Premises and equipment useful life		30 years