Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2025	Nov. 30, 2024	Nov. 30, 2025	Nov. 30, 2024
Statement of Comprehensive Income [Abstract]
Net earnings attributable to controlling interest	$ 18.8	$ 12.8	$ 55.6	$ 41.2
Net earnings attributable to noncontrolling interests	2.7	3.3	4.5	7.1
Net earnings	21.5	16.1	60.1	48.3
Other comprehensive income, net of tax
Foreign currency translation, net	1.1	(4.8)	1.7	(2.7)
Net investment hedge	(0.6)	0.0	(0.6)	0.0
Pension liability adjustment	0.0	(1.0)	0.0	(1.0)
Cash flow hedges	1.4	(0.1)	1.4	0.0
Other comprehensive income (loss)	1.9	(5.9)	2.5	(3.7)
Comprehensive income	23.4	10.2	62.6	44.6
Comprehensive income attributable to noncontrolling interests	2.7	3.3	4.5	7.1
Comprehensive income attributable to Worthington Steel	$ 20.7	$ 6.9	$ 58.1	$ 37.5