CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable-trade, allowance for doubtful accounts	$ 6.0	$ 5.8
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding ( in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	700,000,000	700,000,000
Common stock, shares issued (in shares)	90,573,690	88,887,915
Common stock, shares outstanding ( in shares)	82,694,850	88,426,742
Common shares held in treasury, (in shares)	7,878,840	461,173

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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