BUSINESS SEGMENTS (Summary of Certain Financial Information from Continuing Operations by Reportable Segment and Major Product) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2023	May 31, 2022	May 31, 2023	May 31, 2022	Aug. 31, 2022
Segment Reporting Information [Line Items]
Net sales	$ 2,344,989	$ 2,515,727	$ 6,590,305	$ 6,506,416
Adjusted EBITDA	374,078	465,280	1,073,501	1,343,421
Total assets	6,520,860		6,520,860		$ 6,237,027
Segments \| Continuing Operations
Segment Reporting Information [Line Items]
Net sales	2,344,989	2,515,727	6,590,305	6,506,416
Adjusted EBITDA	374,078	465,280	1,073,501		1,343,421
Total assets	6,520,860		6,520,860		6,237,027
Segments \| North America
Segment Reporting Information [Line Items]
Net sales	1,987,535	2,033,150	5,445,367	5,300,996
Adjusted EBITDA	402,175	379,355	1,079,442		1,183,342
Total assets	4,837,341		4,837,341		4,467,314
Segments \| Europe
Segment Reporting Information [Line Items]
Net sales	353,294	484,564	1,115,440	1,209,378
Adjusted EBITDA	9,618	120,974	87,072		281,955
Total assets	1,270,636		1,270,636		1,056,101
Segments \| Unaffiliated Customers
Segment Reporting Information [Line Items]
Net sales	2,344,989	2,515,727	6,590,305	6,506,416
Segments \| Unaffiliated Customers \| North America
Segment Reporting Information [Line Items]
Net sales	1,985,519	2,033,142	5,440,760	5,300,988
Segments \| Unaffiliated Customers \| Europe
Segment Reporting Information [Line Items]
Net sales	352,694	484,005	1,113,582	1,207,916
Segments \| Raw materials
Segment Reporting Information [Line Items]
Net sales	391,416	442,577	1,009,208	1,175,434
Segments \| Raw materials \| North America
Segment Reporting Information [Line Items]
Net sales	385,449	435,171	993,480	1,155,204
Segments \| Raw materials \| Europe
Segment Reporting Information [Line Items]
Net sales	5,967	7,406	15,728	20,230
Segments \| Steel Products
Segment Reporting Information [Line Items]
Net sales	1,021,265	1,219,572	2,941,994	3,124,220
Segments \| Steel Products \| North America
Segment Reporting Information [Line Items]
Net sales	752,153	851,762	2,088,339	2,192,851
Segments \| Steel Products \| Europe
Segment Reporting Information [Line Items]
Net sales	269,112	367,810	853,655	931,369
Segments \| Downstream products
Segment Reporting Information [Line Items]
Net sales	705,551	676,235	1,996,368	1,779,997
Segments \| Downstream products \| North America
Segment Reporting Information [Line Items]
Net sales	659,103	587,568	1,840,210	1,561,717
Segments \| Downstream products \| Europe
Segment Reporting Information [Line Items]
Net sales	46,448	88,667	156,158	218,280
Segments \| Construction-related solutions
Segment Reporting Information [Line Items]
Net sales	172,250	130,766	473,912	296,903
Segments \| Construction-related solutions \| North America
Segment Reporting Information [Line Items]
Net sales	150,348	121,285	415,184	287,422
Segments \| Construction-related solutions \| Europe
Segment Reporting Information [Line Items]
Net sales	21,902	9,481	58,728	9,481
Segments \| Other
Segment Reporting Information [Line Items]
Net sales	54,507	46,577	168,823	129,862
Segments \| Other \| North America
Segment Reporting Information [Line Items]
Net sales	38,466	37,356	103,547	103,794
Segments \| Other \| Europe
Segment Reporting Information [Line Items]
Net sales	9,265	10,641	29,313	28,556
Segments \| New Markets Tax Credit Transactions \| North America
Segment Reporting Information [Line Items]
Net sales			17,700
Segments \| Corporate
Segment Reporting Information [Line Items]
Net sales	4,160	(1,987)	29,498
Adjusted EBITDA	(37,715)	(35,049)
Segments \| Corporate \| Unaffiliated Customers
Segment Reporting Information [Line Items]
Net sales	6,776	(1,420)	35,963	(2,488)
Segments \| Corporate \| Raw materials
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Segments \| Corporate \| Steel Products
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Segments \| Corporate \| Downstream products
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Segments \| Corporate \| Construction-related solutions
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Segments \| Corporate \| Other
Segment Reporting Information [Line Items]
Net sales	6,776	(1,420)	35,963	(2,488)
Segments \| Corporate and Other
Segment Reporting Information [Line Items]
Net sales				(3,958)
Adjusted EBITDA			(93,013)		(121,876)
Total assets	412,883		412,883		$ 713,612
Intersegment
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Intersegment \| North America
Segment Reporting Information [Line Items]
Net sales	2,016	8	4,607	8
Intersegment \| Europe
Segment Reporting Information [Line Items]
Net sales	600	559	1,858	1,462
Intersegment \| Corporate
Segment Reporting Information [Line Items]
Net sales	$ (2,616)	$ (567)	$ (6,465)	$ (1,470)