GOODWILL AND OTHER INTANGIBLE ASSETS (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Goodwill	$ 64,915,000	$ 64,915,000	$ 66,373,000	$ 66,383,000
Goodwill impairment charges		1,982,000	0
Amortization expense for intangible assets		$ 2,300,000	3,600,000	6,900,000
Intangible assets excluding favorable land leases
Weighted average remaining useful lives		7 years
Favorable land leases
Weighted average remaining useful lives		48 years
One reporting unit within Americas Fabrication
Goodwill	$ 51,600,000	$ 51,600,000	51,300,000
Reporting unit, percentage of fair value in excess of carrying amount (percent)	13.50%	13.50%
International Marketing and Distribution
Goodwill	$ 0	$ 0	1,982,000	1,912,000
Goodwill impairment charges	2,000,000	1,982,000
Americas Recycling
Goodwill	$ 0	0	$ 0	0
Goodwill impairment charges		$ 0		$ 7,300,000