Quarterly report pursuant to Section 13 or 15(d)

GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Narrative) (Details)

v3.8.0.1
GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Cost of Sales [Member]          
Goodwill [Line Items]          
Amortization expense relating to intangible assets $ 0.5 $ 1.2 $ 1.5 $ 3.8  
U.S. Iron Ore [Member]          
Goodwill [Line Items]          
Goodwill $ 2.0   $ 2.0   $ 2.0