EMPLOYEE BENEFIT PLANS (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) plan	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 17	$ 16
Interest cost	6	10
Amortization of prior service cost	19	18
Amortization of gain	(13)	(11)
Net periodic benefit cost	$ 29	$ 33
Defined Benefit Plan Disclosure [Line Items]
Number of savings plan | plan	2
Benefit obligation	$ 1,100		$ 1,076
Deferred compensation liability	2,830		1,982
Related rabbi trust assets	2,832		1,982
Maximum
Defined Benefit Plan Disclosure [Line Items]
Historical cash payments for retirement medical plan claims per year	$ 100
Postretirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit plans | plan	2
Defined Benefit Pension Plan | Chemogas
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	$ 584		$ 596