NATURE OF OPERATIONS (Narrative) (Details)	12 Months Ended
	Aug. 31, 2016 scrap_processing_facility Components segments
Number of business segments | segments	5
Number of geographic divisions | Components	2
CMC Americas Division
Number of business segments | segments	3
CMC International Division
Number of business segments | segments	2
Americas Mills
Number of scrap processing facilities | scrap_processing_facility	10
United States
Number of divisions | Components	2
Singapore
Number of recycling facilities | Components	1