RETIREMENT AND POSTRETIREMENT PLANS - Weighted average allocation by asset category (Details)	Dec. 31, 2022	Dec. 31, 2021
BNB Bank Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	100.00%	100.00%
BNB Bank Pension Plan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	51.00%	60.00%
BNB Bank Pension Plan | Debt securities (bond mutual funds)
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	46.00%	37.00%
BNB Bank Pension Plan | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	3.00%	3.00%
Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	100.00%	100.00%
Employee Retirement Plan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	51.00%	54.00%
Employee Retirement Plan | Debt securities (bond mutual funds)
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	47.00%	42.00%
Employee Retirement Plan | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Actual Asset category	2.00%	4.00%