RETIREMENT AND POSTRETIREMENT PLANS - Major assumptions utilized to determine the net periodic cost of the Plan (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Employee Retirement Plan
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate used for net periodic benefit cost	4.90%	2.55%	2.15%
Discount rate used to determine benefit obligation at period end	4.70%	4.90%	2.55%
Expected long-term return on plan assets used for net periodic benefit cost	7.00%	7.00%	7.00%
Expected long-term return on plan assets used to determine benefit obligation at period end	7.00%	7.00%	7.00%
BNB Bank Pension Plan
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate used for net periodic benefit cost	4.98%	2.69%
Discount rate used to determine benefit obligation at period end	4.79%	4.98%
Expected long-term return on plan assets used for net periodic benefit cost	7.25%	7.25%
Expected long-term return on plan assets used to determine benefit obligation at period end	7.25%	7.25%