EMPLOYEE BENEFIT PLANS - Change in PBO and Assets and Reconciliations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amounts Recognized in the Consolidated Balance Sheets Consist of::
Noncurrent liabilities	$ (25,311)	$ (29,800)
Pension Benefits
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	79,559	87,986
Service cost	0	0	$ 0
Interest cost	3,197	3,021	3,259
Actuarial loss (gain)	10,828	(8,160)
Benefits paid	(3,323)	(3,288)
Projected benefit obligation at end of year	90,261	79,559	87,986
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	50,949	57,377
Actual return on plan assets	12,975	(4,638)
Employer contributions	6,413	2,829
Benefits paid	(3,284)	(4,002)
Other expense	(593)	(617)
Fair value of plan assets at end of year	66,460	50,949	57,377
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Net accrued benefit cost	(23,801)	(28,610)
Amounts Recognized in the Consolidated Balance Sheets Consist of::
Current liabilities	(86)	(86)
Noncurrent liabilities	(23,715)	(28,524)
Net amount recognized	(23,801)	(28,610)
Postretirement
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	1,303	1,420
Service cost	6	7	6
Interest cost	54	38	53
Actuarial loss (gain)	285	(149)
Benefits paid	(14)	(13)
Projected benefit obligation at end of year	1,634	1,303	1,420
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	14	13
Benefits paid	(14)	(13)
Other expense	0	0
Fair value of plan assets at end of year	0	0	$ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Net accrued benefit cost	(1,634)	(1,303)
Amounts Recognized in the Consolidated Balance Sheets Consist of::
Current liabilities	(38)	(27)
Noncurrent liabilities	(1,596)	(1,276)
Net amount recognized	$ (1,634)	$ (1,303)