Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowances for doubtful accounts	$ 8.4	$ 8.5
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	36,185,829	35,799,994
Common stock, shares outstanding (shares)	36,185,829	35,799,994
Treasury stock (shares)	760,782

Amount of allowance for credit loss on accounts receivable, classified as current.

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