RETIREMENT AND POSTRETIREMENT PLANS - Change in Accumulated Other Comprehensive Loss from Employee Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Gain (loss) recognized during the year	$ (6,563)	$ (2,817)	$ 296
Curtailment credit	(1,543)	1,651
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(6,181)	(5,924)
Retirement Plans [Member]
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Gain (loss) recognized during the year	2,193
Balance at the end of the period	2,193
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(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)	(1,494)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total		1,228
Employee Retirement Plan
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Balance at beginning of period	(7,119)	(7,506)
Amortization of unrealized loss	825	914
Gain (loss) recognized during the year	2,197	(527)
Balance at the end of the period	(4,097)	(7,119)	(7,506)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	$ 2,808	4,858
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)
Balance at the end of the period			$ 188