SEGMENT INFORMATION (External Net Sales from Continuing Operations by Major Product) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2026	May 31, 2025	May 31, 2026	May 31, 2025
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 2,483,245	$ 2,019,984	$ 6,735,570	$ 5,683,962
Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	2,475,190	2,007,330	6,704,935	5,648,530
Intersegment Eliminations
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	33,223	35,611	95,581	94,503
North America Steel Group
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	1,809,919	1,579,603	5,121,243	4,517,698
North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	1,789,381	1,562,286	5,058,760	4,467,771
North America Steel Group \| Intersegment Eliminations
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	20,538	17,317	62,483	49,927
Europe Steel Group
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	292,114	248,320	741,435	656,992
Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	291,235	247,590	738,899	655,026
Europe Steel Group \| Intersegment Eliminations
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	879	730	2,536	1,966
Construction Solutions Group
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	406,380	215,018	937,838	568,343
Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	394,574	197,454	907,276	525,733
Construction Solutions Group \| Intersegment Eliminations
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	11,806	17,564	30,562	42,610
Corporate and Other
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	(25,168)	(22,957)	(64,946)	(59,071)
Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	8,055	12,654	30,635	35,432
Segment Eliminations \| Intersegment Eliminations
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	(33,223)	(35,611)	(95,581)	(94,503)
Raw materials \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	460,816	337,624	1,193,727	976,010
Raw materials \| North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	453,206	331,123	1,174,806	959,083
Raw materials \| Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	7,610	6,501	18,921	16,927
Raw materials \| Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Raw materials \| Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Steel products \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	951,024	864,526	2,706,351	2,404,021
Steel products \| North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	715,837	666,298	2,112,559	1,884,312
Steel products \| Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	235,187	198,228	593,792	519,709
Steel products \| Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Steel products \| Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Downstream products \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	646,326	586,280	1,811,261	1,674,806
Downstream products \| North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	564,242	506,639	1,601,255	1,462,696
Downstream products \| Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	36,781	33,639	92,005	92,551
Downstream products \| Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	45,303	46,002	118,001	119,559
Downstream products \| Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Construction products \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	81,406	78,219	245,744	219,931
Construction products \| North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Construction products \| Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Construction products \| Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	81,406	78,219	245,744	219,931
Construction products \| Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Ground stabilization solutions \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	85,779	68,560	208,252	173,266
Ground stabilization solutions \| North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Ground stabilization solutions \| Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Ground stabilization solutions \| Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	85,779	68,560	208,252	173,266
Ground stabilization solutions \| Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	0	0	0	0
Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	85,028	84,775	255,765	235,928
Other \| North America Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	56,096	58,226	170,140	161,680
Other \| Europe Steel Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	11,657	9,222	34,181	25,839
Other \| Construction Solutions Group \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	9,220	4,673	20,809	12,977
Other \| Corporate and Other \| Segments
Entity-Wide Information, Revenue from External Customer [Line Items]
Net sales	$ 8,055	$ 12,654	$ 30,635	$ 35,432

COMMERCIAL METALS Co 10-Q