BENEFIT PLANS (Combined Funded Status of Plans and their Reconciliation with Related Amounts Recognized in Consolidated Financial Statements II) (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in Benefit Obligation
Projected benefit obligation at beginning of year	$ 40,834	$ 43,480
Service cost	1,317	1,357	$ 1,167
Interest cost	1,388	1,240	1,260
Actuarial loss	2,677	856
Benefits paid	(5,029)	(6,099)	(4,871)
Projected benefit obligation at end of year	41,187	40,834	43,480
Change in Fair Value of Plan Assets
Fair value of assets at beginning of year	0	0
Actual return on plan assets	0	0
Fair value of assets at end of year	0	0	$ 0
Funded status	(41,187)	(40,834)
Amounts Recognized in the Consolidated Balance Sheets
Current liabilities	(5,339)	(5,560)
Noncurrent liabilities	(35,848)	(35,274)
Net amount recognized	(41,187)	(40,834)
Amounts Recognized in Accumulated Other Comprehensive Income
Net actuarial gain	(14,642)	(18,624)
Prior service credit	(7,575)	(11,494)
Total amount recognized	$ (22,217)	$ (30,118)