EMPLOYEE BENEFIT PLANS (Details) $ in Thousands			6 Months Ended
	Jan. 01, 2021 numberOfPlan	Dec. 31, 2020 USD ($) numberOfPlan	Jun. 30, 2021 USD ($) numberOfPlan	Jun. 30, 2020 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of savings plan | numberOfPlan	1	2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Deferred compensation liability		$ 3,581	$ 5,714
Related rabbi trust assets		3,581	$ 5,714
Postretirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit plans | numberOfPlan			2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			$ 43	$ 34
Interest cost			12	13
Amortization of prior service cost			37	38
Amortization of gain			12	26
Net periodic benefit cost			80	59
Benefit obligation		1,374	1,429
Historical cash payments for retirement medical plan claims per year (less than)			100
Defined Benefit Pension Plan | Chemogas Defined Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			35	52
Interest cost			7	10
Expected return on plan assets			(18)	(8)
Amortization of gain			2	0
Net periodic benefit cost			26	$ 54
Benefit obligation		$ 950	$ 945