Business Segment Information - Sales by Product and Services (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	May 31, 2020	Feb. 29, 2020	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2020	May 31, 2019	May 31, 2018
Net sales	$ 416.5	$ 553.1	$ 560.9	$ 541.5	$ 562.7	$ 529.5	$ 493.3	$ 466.3	$ 2,072.0	$ 2,051.8	$ 1,748.3
Aviation supply chain
Net sales									1,434.3	1,395.2	1,082.9
Maintenance, repair and overhaul services
Net sales									529.9	525.4	552.9
Mobility products
Net sales									$ 107.8	$ 131.2	$ 112.5