SUBSEQUENT EVENTS SUBSEQUENT EVENTS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2017	Jul. 18, 2017	Jun. 30, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Contingent Liabilities recognized in Consolidated Financials			$ 38.5	$ 37.2
Wabush Scully Mine Sale [Domain]
Subsequent Event [Line Items]
Contingent Liabilities recognized in Consolidated Financials		$ 38.5
Scenario, Forecast [Member] | Wabush Scully Mine Sale [Domain]
Subsequent Event [Line Items]
Gain on Sale of Wabush Scully Mine	$ 30.0