COMMITMENTS AND CONTINGENCIES (Narrative) (Details)	1 Months Ended						3 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($)	Oct. 31, 2018 mi	Dec. 31, 2017 USD ($)	Sep. 30, 2017 item	Mar. 31, 2016 mi	May 31, 2007 entity mi	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) item	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)
Loss Contingencies [Line Items]
Asset retirement obligations	$ 223,497,000		$ 218,117,000				$ 225,726,000	$ 226,084,000	$ 224,067,000	$ 225,726,000	$ 215,421,000
Number of groundwater extraction wells | item				2
Contingency loss									0
Operating lease liabilities									$ 421,361,000
Parent Company [Member]
Loss Contingencies [Line Items]
Judge ruled allocation of fault among defendants, percentage			15.00%
New York Water District Cases [Member]
Loss Contingencies [Line Items]
Number of cases | item									24
EPA Administrative Order [Member]
Loss Contingencies [Line Items]
Total amount of damages claimed	$ 193,750
Cooperating Parties Group [Member]
Loss Contingencies [Line Items]
Number of other companies to perform a Remedial Investigation/ Feasibility Study related to the Lower Passaic River Clean-Up lawsuit | entity						70
Number of miles of the River used in the Remedial Investigation/Feasibility Study | mi						17
Number of miles for bank-to-bank dredging remedy | mi		9			8
Occidental Chemical Co [Member]
Loss Contingencies [Line Items]
Judge ruled allocation of fault among defendants, percentage			50.00%
Texas Brine [Member]
Loss Contingencies [Line Items]
Judge ruled allocation of fault among defendants, percentage			35.00%
Number of cases | item									2
Minimum [Member] | NAFTA Arbitration [Member]
Loss Contingencies [Line Items]
Arbitration period									2 years
Maximum [Member] | EPA [Member]
Loss Contingencies [Line Items]
Estimated implementation costs									$ 1,380,000,000
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Outstanding standby letters of credit									53,250,000
Hewitt Landfill Matter [Member]
Loss Contingencies [Line Items]
Life-to-date total accruals									$ 34,271,000
Increase in accrual of liability for claims and litigation							$ 10,392,000	$ 8,640,000		$ 19,032,000