ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY INFORMATION - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) loan	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($) loan	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan workout and other credit costs	$ 1,802	$ 1,684	$ 3,671	$ 1,477
Allowance for credit losses related to other accounts receivable	2,268	0	2,268	0	$ 0	$ 2,811	$ 0	$ 0
Various Modifications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unused commitments to extend credit	4,000		$ 4,000		$ 18,600
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans in the process of foreclosure | loan			30		31
Total loans outstanding			$ 5,600		$ 5,600
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans in the process of foreclosure | loan			34		15
Total loans outstanding			$ 43,000		$ 6,600
Residential and Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan workout and other credit costs	$ 1,100	$ 800	$ 3,300	$ 700
Impairment loans, charge off period			90 days