INVESTMENT SECURITIES - Allowance for credit losses to HTM securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Allowance for credit losses:
Beginning balance	$ 0
Total ending allowance balance	71
Corporate bonds
Allowance for credit losses:
Beginning balance	0
Provision for credit losses	0
Securities charged-off (recoveries)	0
Total ending allowance balance	71
Corporate bonds | Cumulative change in accounting principle
Allowance for credit losses:
Beginning balance	71
Corporate CMO
Allowance for credit losses:
Beginning balance	0
Provision for credit losses	0
Securities charged-off (recoveries)	0
Total ending allowance balance	0
Corporate CMO | Cumulative change in accounting principle
Allowance for credit losses:
Beginning balance	$ 0