Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May 31, 2020	May 31, 2019
Statement Of Financial Position [Abstract]
Receivables, allowances	$ 1,521	$ 1,150
Other intangible assets, accumulated amortization	$ 92,774	$ 87,759
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	54,616,485	55,467,525
Common shares, shares outstanding	54,616,485	55,467,525
Accumulated other comprehensive income (loss), taxes	$ 7,922	$ 7,100