Earnings (Loss) Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Basic EPS:
Net income (loss)	$ 18.2	$ 0.2
Less dividends on preferred shares	(5.4)	(5.0)
Less income allocated to preferred shareholders	(6.2)	0.0
Net income (loss) available/allocated to common shareholders - basic	6.6	(4.8)
Diluted EPS:
Less income allocated to preferred shareholders	(5.0)	0.0
Net income (loss) available/(allocated) to common shareholders - diluted	$ 7.8	$ (4.8)
Basic weighted-average common shares (in shares)	114,441,043	109,802,632
Add: Effect of dilutive equity awards (in shares)	11,893,514	0
Add: Effect of dilutive warrants (in shares)	43,285,621	0
Diluted weighted average common shares (in shares)	169,620,178	109,802,632
Net income (loss) per common share (basic) (in dollars per share)	$ 0.06	$ (0.04)
Net income (loss) per common share (diluted) (in dollars per share)	$ 0.05	$ (0.04)