Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Accounts receivable, allowance	$ 2.3	$ 3.7
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	295,885,508	137,812,559
Common stock, shares outstanding (in shares)	277,492,322	121,144,038
Treasury stock, shares (in shares)	18,393,186	16,668,521
Redeemable Convertible Preferred Stock
Preferred stock, dividend rate (percentage)	8.00%	8.00%
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	0	370,000
Preferred stock, shares issued (in shares)	0	288,497
Preferred stock, shares outstanding (in shares)	0	288,497
Preferred stock, aggregate liquidation value		$ 294.3
Related Party
Accounts receivable, allowance	$ 0.1	$ 0.1

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

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