RETIREMENT AND POSTRETIREMENT PLANS - Change in Accumulated Other Comprehensive Loss from Employee Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Gain (loss) recognized during the year	$ 2,062	$ (6,563)	$ (2,817)
Curtailment credit		(1,543)	1,651
Period end component of accumulated other comprehensive loss, net of tax	(94,379)	(6,181)
BNB Bank Pension Plan
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Balance at beginning of period	2,193
Gain (loss) recognized during the year	(2,358)	2,193
Balance at the end of the period	(165)	2,193
Period end component of accumulated other comprehensive loss, net of tax	113	(1,503)
RETIREMENT PLANS | BMP and Outside Director Retirement Plan
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Balance at beginning of period		(1,820)	(1,494)
Amortization of unrealized loss			179
Gain (loss) recognized during the year		277	(505)
Curtailment credit		1,543
Balance at the end of the period			(1,820)
Period end component of accumulated other comprehensive loss, net of tax			1,228
Employee Retirement Plan
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Balance at beginning of period	(4,097)	(7,119)
Amortization of unrealized loss	261	825
Gain (loss) recognized during the year	(1,487)	2,197
Balance at the end of the period	(5,323)	(4,097)	(7,119)
Period end component of accumulated other comprehensive loss, net of tax	$ 3,649	$ 2,808
POSTRETIREMENT PLANS
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Balance at beginning of period			188
Amortization of unrealized loss			(9)
Recognition of prior service cost			(74)
Gain (loss) recognized during the year			$ (105)