Consolidated Balance Sheets (Parenthetical) - USD ($)	May 31, 2022	May 31, 2021
Statement Of Financial Position [Abstract]
Receivables, allowances	$ 1,292,000	$ 608,000
Other intangible assets, accumulated amortization	$ 93,973,000	$ 80,513,000
Preferred shares, without par value
Preferred shares, shares authorized	1,000,000	1,000,000
Preferred shares, shares issued	0	0
Preferred shares, shares outstanding	0	0
Common stock, without par value
Common shares, authorized	150,000,000	150,000,000
Common shares, shares issued	48,380,112	51,330,347
Common shares, shares outstanding	48,380,112	51,330,347
Accumulated other comprehensive income, taxes	$ 2,049,000	$ (12,550,000)