Segment Information Segment Revenue Reconciliation to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2017	May 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 477,088	$ 351,604	$ 1,193,333	$ 961,880
Auto and Metals Recycling
Segment Reporting Information [Line Items]
Revenues	395,124	280,680	1,000,482	760,663
Steel Manufacturing Business
Segment Reporting Information [Line Items]
Revenues	81,964	70,924	192,851	201,217
Operating Segments | Auto and Metals Recycling
Segment Reporting Information [Line Items]
Revenues	430,047	306,851	1,084,354	829,628
Less: Intersegment revenues | Auto and Metals Recycling
Segment Reporting Information [Line Items]
Revenues	$ (34,923)	$ (26,171)	$ (83,872)	$ (68,965)