RETIREMENT AND POSTRETIREMENT PLANS - Employee Retirement Plans investments measured at fair value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	$ 21,303	$ 22,593	$ 28,693
Expected annual rates of return	7.00%	7.00%	7.00%
Percentage of cumulative long term return on index	9.00%
Percentage of cumulative long term return on bonds	5.00%
Employee Retirement Plan's target allocation, expected annual rate of return	7.00%	7.00%
Actuarial (gain) loss	$ 384	$ (5,004)
Employee Retirement Plan | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	58	541
Employee Retirement Plan | U.S. large cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		8,398
Employee Retirement Plan | U.S. mid cap/small cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		2,348
Employee Retirement Plan | International
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		2,718
Employee Retirement Plan | Equities blend
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		192
Employee Retirement Plan | Corporate
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		1,305
Employee Retirement Plan | Government
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	21,245	2,527
Employee Retirement Plan | Mortgage-backed
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		586
Employee Retirement Plan | High yield bonds and bond funds
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		3,978
Employee Retirement Plan | Domestic Mid Cap.
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	21,303	22,593
Employee Retirement Plan | Level 1 Inputs | U.S. large cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		8,398
Employee Retirement Plan | Level 1 Inputs | U.S. mid cap/small cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		2,348
Employee Retirement Plan | Level 1 Inputs | International
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		2,718
Employee Retirement Plan | Level 1 Inputs | Equities blend
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		192
Employee Retirement Plan | Level 1 Inputs | Government
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	21,245	2,527
Employee Retirement Plan | Level 1 Inputs | Domestic Mid Cap.
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	21,245	16,183
Employee Retirement Plan | Level 2 Inputs | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	58	541
Employee Retirement Plan | Level 2 Inputs | Corporate
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		1,305
Employee Retirement Plan | Level 2 Inputs | Mortgage-backed
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		586
Employee Retirement Plan | Level 2 Inputs | High yield bonds and bond funds
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		3,978
Employee Retirement Plan | Level 2 Inputs | Domestic Mid Cap.
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	58	6,410
BNB Bank Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	$ 38,170	$ 38,572	$ 47,857
Expected annual rates of return	7.25%	7.25%
Percentage of cumulative long term return on index	9.00%
Percentage of cumulative long term return on bonds	5.00%
Employee Retirement Plan's target allocation, expected annual rate of return	7.25%
Actuarial (gain) loss	$ (883)	$ (7,111)
BNB Bank Pension Plan | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	317	1,001
BNB Bank Pension Plan | U.S. large cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		14,310
BNB Bank Pension Plan | U.S. mid cap/small cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		4,094
BNB Bank Pension Plan | International
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		4,658
BNB Bank Pension Plan | Equities blend
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		308
BNB Bank Pension Plan | Corporate
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		2,203
BNB Bank Pension Plan | Government
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	37,853	4,275
BNB Bank Pension Plan | Mortgage-backed
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		979
BNB Bank Pension Plan | High yield bonds and bond funds
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		6,744
BNB Bank Pension Plan | Domestic Mid Cap.
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		38,572
BNB Bank Pension Plan | Level 1 Inputs
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	37,853
BNB Bank Pension Plan | Level 1 Inputs | U.S. large cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		14,310
BNB Bank Pension Plan | Level 1 Inputs | U.S. mid cap/small cap
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		4,094
BNB Bank Pension Plan | Level 1 Inputs | International
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		4,658
BNB Bank Pension Plan | Level 1 Inputs | Equities blend
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		308
BNB Bank Pension Plan | Level 1 Inputs | Government
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	37,853	4,275
BNB Bank Pension Plan | Level 1 Inputs | Domestic Mid Cap.
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		27,645
BNB Bank Pension Plan | Level 2 Inputs
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	317
BNB Bank Pension Plan | Level 2 Inputs | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets	$ 317	1,001
BNB Bank Pension Plan | Level 2 Inputs | Corporate
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		2,203
BNB Bank Pension Plan | Level 2 Inputs | Mortgage-backed
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		979
BNB Bank Pension Plan | Level 2 Inputs | High yield bonds and bond funds
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		6,744
BNB Bank Pension Plan | Level 2 Inputs | Domestic Mid Cap.
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		$ 10,927