Restructuring Charges and Other Exit-Related Costs - Restructuring Costs and Other Exit-Related Costs by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Feb. 28, 2015	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 10,614	$ 6,401	$ 7,906
Total restructuring charges and other exit-related costs	$ 8,000	17,116	6,967	7,906
Total restructuring charges to date		29,933
Total expected restructuring charges		31,810
Total restructuring charges and other exit-related costs, incurred to date		37,001
Asset impairments and accelerated depreciation
Restructuring Cost and Reserve [Line Items]
Other exit-related costs, including discontinued operations		6,502	566	0
Total exit-related costs
Restructuring Cost and Reserve [Line Items]
Other exit-related costs, including discontinued operations		6,502	566	0
Operating Segments | Auto and Metals Recycling
Restructuring Cost and Reserve [Line Items]
Restructuring charges		6,944	5,191	2,987
Total restructuring charges to date		17,016
Total expected restructuring charges		18,300
Operating Segments | Auto and Metals Recycling | Asset impairments and accelerated depreciation
Restructuring Cost and Reserve [Line Items]
Other exit-related costs, including discontinued operations		3,836	566	0
Total restructuring charges and other exit-related costs, incurred to date		4,402
Unallocated (Corporate)
Restructuring Cost and Reserve [Line Items]
Restructuring charges		2,228	1,073	4,919
Total restructuring charges to date		11,339
Total expected restructuring charges		11,860
Segment Reconciling Items | Total exit-related costs
Restructuring Cost and Reserve [Line Items]
Other exit-related costs, including discontinued operations		6,502	566	0
Total restructuring charges and other exit-related costs, incurred to date		7,068
Discontinued operations | Segment Reconciling Items
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,442	137	0
Total restructuring charges and other exit-related costs		4,108	137	0
Total restructuring charges to date		1,578
Total expected restructuring charges		1,650
Discontinued operations | Segment Reconciling Items | Asset impairments and accelerated depreciation
Restructuring Cost and Reserve [Line Items]
Other exit-related costs, including discontinued operations		2,666	$ 0	$ 0
Total restructuring charges and other exit-related costs, incurred to date		$ 2,666