Quarterly report pursuant to Section 13 or 15(d)

SUBSEQUENT EVENTS SUBSEQUENT EVENTS (Narrative) (Details)

v3.7.0.1
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