EMPLOYEE BENEFIT PLANS (Components of the net periodic benefit cost) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of Net Periodic Benefit Costs:
Settlement Loss	$ 500	$ 2,000	$ 0	$ 2,500	$ 0
Defined Benefit Pension Plan [Member]
Components of Net Periodic Benefit Costs:
Service Cost	1,743		1,457	5,229	4,371
Interest Cost	1,221		1,400	3,664	4,212
Expected Return on Plan Assets	(2,787)		(2,748)	(8,361)	(8,245)
Prior Service Cost Amortization	4		4	11	11
Net Loss Amortization	1,691		974	5,073	2,959
Settlement Loss	500		0	2,500	0
Special Termination Charge	0		0	0	61
Net Periodic Benefit Cost	$ 2,372		$ 1,087	$ 8,116	$ 3,369
Discount Rate	2.88%		3.53%	2.88%	3.53%
Long-Term Rate of Return on Assets	6.75%		7.00%	6.75%	7.00%
Supplemental Executive Retirement Plan [Member]
Components of Net Periodic Benefit Costs:
Service Cost	$ 9		$ 10	$ 27	$ 21
Interest Cost	61		83	183	238
Prior Service Cost Amortization	69		109	157	218
Net Loss Amortization	243		93	683	410
Net Periodic Benefit Cost	$ 382		$ 295	$ 1,050	$ 887
Discount Rate	2.38%		3.16%	2.38%	3.16%