EMPLOYEE RETIREMENT PLANS - Schedule of net periodic pension cost (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining projected benefit obligation	3.36%	4.39%
Long-term rate of return on plan assets	7.00%	7.00%
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining projected benefit obligation	4.38%	3.70%
Discount rate in effect for determining service cost	0.00%	0.00%
Discount rate in effect for determining interest cost	4.05%	3.33%
Long-term rate of return on plan assets	7.00%	7.00%
Supplemental Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for determining projected benefit obligation	4.42%	3.75%
Discount rate in effect for determining service cost	0.00%	3.83%
Discount rate in effect for determining interest cost	4.19%	3.51%
Long-term rate of return on plan assets	0.00%	0.00%