Net Income (Loss) Per Share - Components and Calculation of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
		Mar. 31, 2022		Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Numerator:
Net income (loss) from continuing operations		$ 55.8		$ 68.1	$ 104.5	$ 79.8	$ (10.5)
Dividends on Preferred Stock		(6.0)					(6.0)
Undistributed income from continuing operations allocated to participating securities		(6.1)
Net income (loss) from continuing operations attributable to common stockholders - Basic and Diluted		43.7					(16.5)
Net income (loss) from discontinued operations attributable to common stockholders - Basic and Diluted							4.2
Net income (loss) attributable to common stockholders - Basic and Diluted		$ 43.7					$ (12.3)
Denominator:
Weighted-average common shares outstanding - Basic	[1]	70,100,000					69,600,000
Effect of common share equivalents		1,200,000
Weighted-average common shares outstanding - Diluted	[1]	71,300,000					69,600,000
Net income (loss) per share:
Basic - Continuing operations		$ 0.62	[1]	$ 0.78	$ 1.23	$ 0.93	$ (0.24)	[1]
Basic - Discontinued operations	[1]						0.06
Basic net income (loss) per share		0.62	[1]	0.78	1.24	0.89	(0.18)	[1]
Diluted - Continuing operations		0.61	[1]	0.76	1.21	0.91	(0.24)	[1]
Diluted - Discontinued operations	[1]						0.06
Diluted net income (loss) per share		$ 0.61	[1]	$ 0.76	$ 1.22	$ 0.87	$ (0.18)	[1]

[1] See Note 6 for detailed calculations and further discussion.