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Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ (35.5)	$ (58.2)	$ (26.9)	$ (2.7)	$ (4.8)	$ (20.7)	$ (20.7)	$ (34.6)	$ (123.3)	$ (80.8)	$ (66.2)
Amount allocated to common stockholders									100.00%	100.00%	100.00%
Basic and Diluted EPS:
Net income (loss) allocated to common stockholders	$ (35.5)	$ (58.2)	$ (26.9)	$ (2.7)	$ (4.8)	$ (20.7)	$ (20.7)	$ (34.6)	$ (123.3)	$ (80.8)	$ (66.2)
Shares outstanding, basic and diluted (in shares)									89.5	88.8	87.6
Basic and diluted (in dollars per share)									$ (1.38)	$ (0.91)	$ (0.76)

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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