REMEDIAL LIABILITIES (Anticipated Payments) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accrual for Environmental Loss Contingencies, Net [Abstract]
2021	$ 12,718
2022	19,275
2023	11,420
2024	9,073
2025	6,526
Thereafter	75,915
Undiscounted remedial liabilities	134,927
Less: Discount	(20,114)
Total remedial liabilities	$ 114,813	$ 114,173	$ 121,017

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

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Amount of imputed interest necessary to reduce (reconcile) the undiscounted amount of the accrual for environmental loss contingencies to the present value.

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Undiscounted amount of the accrual for environmental loss contingencies.

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Undiscounted amount of accrual for environmental loss contingency to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Undiscounted amount of accrual for environmental loss contingency to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Undiscounted amount of accrual for environmental loss contingency to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Undiscounted amount of accrual for environmental loss contingency to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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