COMMITMENTS AND CONTINGENCIES (Details) - Koppers Pond $ in Millions	1 Months Ended
	Sep. 30, 2017 party	Jun. 30, 2017 party	Jul. 31, 2016 USD ($)	Mar. 31, 2018 USD ($)
Site Contingency [Line Items]
Clean-up phase cost | $			$ 1.9
Number of parties added to cost sharing agreement (party) | party		2
Number of potentially responsible parties (party) | party	9
Percentage of costs allocated to company	10.75%
Accrual for environmental loss contingencies | $				$ 0.2