COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Unsettled legal claims	$ 2,645	$ 4,356
Maximum Vehicular Liability Claim Deductible	5,000
Maximum General Liability Claim Deductible	2,000
Maximum Workers Compensation Claim Deductible	1,000
Self-insurance liabilities related to workers' compensation, vehicular liabilities, and general liability claims recorded	54,100	50,100
Insurance receivables which partially offset self-insurance liabilities	14,900	13,100
Environmental remediation liabilities recorded	$ 2,300	$ 2,200