EMPLOYEE BENEFIT PLANS (Components of the net periodic benefit cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Pension Plan [Member]
Components of Net Periodic Benefit Costs:
Service Cost	$ 1,457	$ 1,529	$ 4,371	$ 4,587
Interest Cost	1,400	1,545	4,212	4,635
Expected Return on Plan Assets	(2,748)	(2,382)	(8,245)	(7,146)
Prior Service Cost Amortization	4	4	11	12
Net Loss Amortization	974	965	2,959	2,895
Special Termination Charge	0	0	61	0
Net Periodic Benefit Cost	$ 1,087	$ 1,661	$ 3,369	$ 4,983
Discount Rate (in percent)	3.53%	4.43%	3.53%	4.43%
Long-Term Rate of Return on Assets (in percent)	7.00%	7.25%	7.00%	7.25%
Supplemental Executive Retirement Plan [Member]
Components of Net Periodic Benefit Costs:
Service Cost	$ 10	$ 0	$ 21	$ 0
Interest Cost	83	87	238	261
Prior Service Cost Amortization	109	0	218	0
Net Loss Amortization	93	190	410	570
Net Periodic Benefit Cost	$ 295	$ 277	$ 887	$ 831
Discount Rate (in percent)	3.16%	4.23%	3.16%	4.23%