Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Feb. 28, 2018	May 31, 2017
Condensed Consolidated Balance Sheets
Accounts receivable, allowances (in dollars)	$ 7.4	$ 4.9
Property, plant and equipment, accumulated depreciation (in dollars)	212.4	207.5
Intangible assets, accumulated amortization (in dollars)	$ 32.7	$ 27.6
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	45,175,302
Treasury stock, shares	10,662,048	10,820,844