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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss	$ (7.8)	$ (5.5)	$ (41.8)	$ (32.4)
Preferred stock dividends	2.6	2.6	5.2	5.2
Net loss applicable to common shareowners - basic and diluted	$ (10.4)	$ (8.1)	$ (47.0)	$ (37.6)
Denominator:
Weighted average common shares outstanding - basic	50.6	50.4	50.6	50.3
Stock-based compensation arrangements	0.0	0.0	0.0	0.0
Weighted average common shares outstanding - diluted	50.6	50.4	50.6	50.3
Basic and diluted net loss per common share	$ (0.21)	$ (0.16)	$ (0.93)	$ (0.75)