PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) plan	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Number of plans covering nonunion employees | plan	1
(Decrease) (Increase) in basis point drop in discount rate	(0.70%)	0.50%
Fair value of plan assets	$ 233,930	$ 273,895
Excess of PBO/ABO plan assets	4,245	0
Pension expense	3,900	5,500	$ 9,800
Foreign Defined Contribution Plans
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Pension expense	$ 1,700	1,000	1,000
Equity investment funds
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Target plan asset allocations (percent)	35.00%
Fixed income funds
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Target plan asset allocations (percent)	65.00%
Union Pension Plan
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Discretionary employer contribution	$ 7,900	0	9,000
Fair value of plan assets	50,600
Projected benefit obligation	46,400
Accumulated benefit obligation	46,400
Nonunion Pension Plan
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Discretionary employer contribution	0	0	43,000
Fair value of plan assets	183,300
Projected benefit obligation	197,200
Accumulated benefit obligation	$ 197,200
Pension Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Number of plans | plan	2
Fair value of plan assets	$ 233,930	273,895	263,027
Excess of PBO/ABO plan assets	4,245	0
Excess of PBO/ABO plan liabilities	$ 13,930	21,671
Other Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Number of plans | plan	2
Fair value of plan assets	$ 0	0	$ 0
Excess of PBO/ABO plan assets	0	0
Excess of PBO/ABO plan liabilities	3,301	$ 3,575
Estimated future employer contributions	$ 300