Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Aug. 31, 2018	May 31, 2018
Condensed Consolidated Balance Sheets
Accounts receivable, allowances (in dollars)	$ 8.5	$ 7.5
Property, plant and equipment, accumulated depreciation (in dollars)	218.6	214.4
Intangible assets, accumulated amortization (in dollars)	$ 34.1	$ 33.3
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, authorized shares	250,000	250,000
Preferred stock, issued shares	0	0
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	45,300,786	45,300,786
Treasury stock, shares	10,259,690	10,585,165