BUSINESS SEGMENTS (Summary of Certain Financial Information from Continuing Operations by Reportable Segment and Major Product) (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Aug. 31, 2021
Segment Reporting Information [Line Items]
Net sales	$ 1,981,801	$ 1,391,803
Adjusted EBITDA from continuing operations	314,022	143,633
Total assets	4,725,258		$ 4,638,671
Segments | Continuing Operations
Segment Reporting Information [Line Items]
Net sales	1,981,801	1,391,803
Adjusted EBITDA from continuing operations	314,022	143,633
Total assets	4,725,258	4,638,671
Segments | North America
Segment Reporting Information [Line Items]
Net sales	1,653,622	1,195,013
Adjusted EBITDA from continuing operations	268,524	155,634
Total assets	3,389,890	3,221,465
Segments | Europe
Segment Reporting Information [Line Items]
Net sales	329,056	194,596
Adjusted EBITDA from continuing operations	79,832	14,470
Total assets	736,872	729,766
Segments | Unaffiliated Customers
Segment Reporting Information [Line Items]
Net sales	1,981,801	1,391,803
Segments | Unaffiliated Customers | North America
Segment Reporting Information [Line Items]
Net sales	1,653,622	1,195,013
Segments | Unaffiliated Customers | Europe
Segment Reporting Information [Line Items]
Net sales	328,562	194,185
Segments | Raw materials
Segment Reporting Information [Line Items]
Net sales	360,052	213,067
Segments | Raw materials | North America
Segment Reporting Information [Line Items]
Net sales	353,092	210,237
Segments | Raw materials | Europe
Segment Reporting Information [Line Items]
Net sales	6,960	2,830
Segments | Steel Products
Segment Reporting Information [Line Items]
Net sales	918,187	609,112
Segments | Steel Products | North America
Segment Reporting Information [Line Items]
Net sales	675,042	457,657
Segments | Steel Products | Europe
Segment Reporting Information [Line Items]
Net sales	243,145	151,455
Segments | Downstream products
Segment Reporting Information [Line Items]
Net sales	584,468	471,502
Segments | Downstream products | North America
Segment Reporting Information [Line Items]
Net sales	514,396	437,029
Segments | Downstream products | Europe
Segment Reporting Information [Line Items]
Net sales	70,072	34,473
Segments | Other
Segment Reporting Information [Line Items]
Net sales	119,094	98,122
Segments | Other | North America
Segment Reporting Information [Line Items]
Net sales	111,092	90,090
Segments | Other | Europe
Segment Reporting Information [Line Items]
Net sales	8,385	5,427
Segments | Corporate
Segment Reporting Information [Line Items]
Net sales	(877)	2,194
Adjusted EBITDA from continuing operations	(34,334)	(26,471)
Segments | Corporate | Unaffiliated Customers
Segment Reporting Information [Line Items]
Net sales	(383)	2,605
Segments | Corporate | Raw materials
Segment Reporting Information [Line Items]
Net sales	0	0
Segments | Corporate | Steel Products
Segment Reporting Information [Line Items]
Net sales	0	0
Segments | Corporate | Downstream products
Segment Reporting Information [Line Items]
Net sales	0	0
Segments | Corporate | Other
Segment Reporting Information [Line Items]
Net sales	(383)	2,605
Segments | Corporate and Other
Segment Reporting Information [Line Items]
Total assets	598,496	687,440
Intersegment
Segment Reporting Information [Line Items]
Net sales	0	0
Intersegment | North America
Segment Reporting Information [Line Items]
Net sales	0	0
Intersegment | Europe
Segment Reporting Information [Line Items]
Net sales	494	411
Intersegment | Corporate
Segment Reporting Information [Line Items]
Net sales	$ (494)	$ (411)