Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May 31, 2021	May 31, 2020
Statement Of Financial Position [Abstract]
Receivables, allowances	$ 608	$ 1,521
Other intangible assets, accumulated amortization	$ 80,513	$ 92,774
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	51,330,347	54,616,485
Common shares, shares outstanding	51,330,347	54,616,485
Accumulated other comprehensive income (loss), taxes	$ (12,550)	$ 7,922