Earnings (Loss) per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings (Loss) per Common Share
Net income	$ 14.4	$ 36.4	$ (87.3)
Basic weighted-average shares	81,561,707	80,713,926	81,808,425
Effect of dilutive securities:
Restricted stock awards	1,253,103	475,236
Diluted weighted-average shares	82,814,810	81,189,162	81,808,425
Basic earnings per share (in dollars per share)	$ 0.18	$ 0.45	$ (1.07)
Diluted earnings per share (in dollars per share)	$ 0.17	$ 0.45	$ (1.07)