The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Unusual Items - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Loss on debt	$ (0.9)	$ 0.0	$ (10.5)	$ 0.0
2 1/4% Notes
Debt Instrument [Line Items]
Extinguishment of debt			154.1
2 1/4% Notes \| Convertible Debt
Debt Instrument [Line Items]
Extinguishment of debt			$ 154.1
Converted instrument, shares settled (in shares)			2.9
Debt instrument interest rate stated percentage	2.25%		2.25%
Loss on debt			$ (10.5)
Unusual Items
Debt Instrument [Line Items]
Merger costs (component of other expense, net)	$ 7.2	0.0	20.8	0.0
Loss on debt	$ (0.9)	$ 0.0	$ (10.5)	$ 0.0