REMEDIAL LIABILITIES (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Environmental Remediation Obligations [Abstract]
Changes in estimates recorded to statement of income (loss)	$ 687	$ 45
Future remediation liability	121,017	$ 124,468	$ 128,007
Possible increase in total remedial liabilities	$ 22,800
Accrual for environmental loss contingencies, threshold for disclosure (as a percent)	5.00%

Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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