Business Segment Information - Reconciliation of segment operating income to income from continuing operations before provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2024	May 31, 2023	May 31, 2022
Business Segment Information
Operating income	$ 129.2	$ 133.9	$ 106.9
Pension settlement charge	(26.7)		(1.4)
Losses related to sale and exit of business	(2.8)	(0.7)	(1.7)
Other income (expense), net	(0.4)	(0.8)	2.2
Interest expense	(43.2)	(12.2)	(2.4)
Interest income	2.2	1.0	0.1
Income from continuing operations before income taxes	58.3	121.2	105.1
Operating segments
Business Segment Information
Operating income	189.7	167.2	134.5
Operating segments | Parts Supply
Business Segment Information
Operating income	109.8	93.7	74.8
Operating segments | Repair & Engineering
Business Segment Information
Operating income	52.5	35.3	29.1
Operating segments | Integrated Solutions
Business Segment Information
Operating income	23.9	30.5	21.4
Operating segments | Expeditionary Services
Business Segment Information
Operating income	3.5	7.7	9.2
Corporate and other
Business Segment Information
Operating income	$ (60.5)	$ (33.3)	$ (27.6)