Business Segment Information - Sales by Segment (Details) $ in Millions	12 Months Ended
	May 31, 2024 USD ($) segment	May 31, 2023 USD ($)	May 31, 2022 USD ($)
Business Segment Information
Number of new operating segments | segment	3
Net sales	$ 2,318.9	$ 1,990.5	$ 1,820.0
Inter-segment Sales
Business Segment Information
Net sales	97.3	99.3	107.7
Total Sales
Business Segment Information
Net sales	2,416.2	2,089.8	1,927.7
Parts Supply
Business Segment Information
Net sales	967.0	818.4	678.3
Parts Supply | Inter-segment Sales
Business Segment Information
Net sales	8.6	19.3	53.2
Parts Supply | Total Sales
Business Segment Information
Net sales	975.6	837.7	731.5
Repair & Engineering
Business Segment Information
Net sales	640.1	533.4	470.7
Repair & Engineering | Inter-segment Sales
Business Segment Information
Net sales	87.8	79.8	54.1
Repair & Engineering | Total Sales
Business Segment Information
Net sales	727.9	613.2	524.8
Integrated Solutions
Business Segment Information
Net sales	641.9	546.9	596.8
Integrated Solutions | Inter-segment Sales
Business Segment Information
Net sales	0.9	0.2	0.1
Integrated Solutions | Total Sales
Business Segment Information
Net sales	642.8	547.1	596.9
Expeditionary Services
Business Segment Information
Net sales	69.9	91.8	74.2
Expeditionary Services | Inter-segment Sales
Business Segment Information
Net sales			0.3
Expeditionary Services | Total Sales
Business Segment Information
Net sales	$ 69.9	$ 91.8	$ 74.5