Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Feb. 28, 2021	May 31, 2020
Receivables
Allowance for doubtful accounts	$ 1.0	$ 1.3
Common stock
Common stock, par value	$ 1.00	$ 1.00
Common stock, authorized shares	600,000,000	600,000,000
Common stock, issued shares	147,564,905	146,993,751
Treasury stock
Treasury stock, common shares	1,282,466	954,858