Earnings Per Common Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net loss	$ (8.2)	$ (13.6)	$ (50.0)	$ (46.0)
Preferred stock dividends	2.6	2.6	7.8	7.8
Net loss applicable to common shareowners - basic and diluted	$ (10.8)	$ (16.2)	$ (57.8)	$ (53.8)
Denominator:
Weighted average common shares outstanding - basic	50.7	50.4	50.6	50.4
Stock-based compensation arrangements	0.0	0.0	0.0	0.0
Weighted average common shares outstanding - diluted	50.7	50.4	50.6	50.4
Basic and diluted net loss per common share	$ (0.21)	$ (0.32)	$ (1.14)	$ (1.07)