Segment Information Segment Revenue Reconciliation to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016
Segment Reporting Information [Line Items]
Revenues	$ 382,084	$ 289,077	$ 716,245	$ 610,275
Auto and Metals Recycling
Segment Reporting Information [Line Items]
Revenues	323,793	230,686	605,358	479,983
Steel Manufacturing Business
Segment Reporting Information [Line Items]
Revenues	58,291	58,391	110,887	130,292
Operating Segments | Auto and Metals Recycling
Segment Reporting Information [Line Items]
Revenues	349,369	249,812	654,307	522,777
Less: Intersegment revenues | Auto and Metals Recycling
Segment Reporting Information [Line Items]
Revenues	$ (25,576)	$ (19,126)	$ (48,949)	$ (42,794)