Goodwill and Other Intangibles - Schedule of other intangible assets subject to amortization (Details) - USD ($)	3 Months Ended		12 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	May 31, 2022
Finite-lived Intangible Assets [Roll Forward]
Beginning balance other intangibles subject to amortization	$ 6,000,000.0	$ 8,400,000	$ 8,400,000
Additions	0	0	0
Amortization expense	(500,000)	(500,000)	(2,000,000.0)
Foreign currency translation	(200,000)	(100,000)	(400,000)
Total other intangibles subject to amortization, net of accumulated amortization of $24.8, $24.1 and $22.5, respectively	5,300,000	7,800,000	6,000,000.0
Accumulated amortization of intangible assets	34,800,000	32,800,000	34,300,000
Total other intangibles not subject to amortization	2,100,000	2,100,000	2,100,000
Total other intangibles	$ 7,400,000	$ 9,900,000	$ 8,100,000