Earnings per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share, Basic and Diluted [Line Items]
Net income	$ 72.7	$ 85.7	$ 196.0	$ 116.4
Weighted average common shares outstanding for basic earnings per share computation (in shares)	103,822,311	106,525,974	103,793,851	102,879,422
Dilutive effects of stock-based compensation (in shares)	4,116	63,725	30,425	55,938
Weighted average common shares outstanding for diluted earnings per common share computation (in shares)	103,826,427	106,589,699	103,824,276	102,935,360
Basic earnings per common share (in dollars per share)	$ 0.70	$ 0.80	$ 1.89	$ 1.13
Diluted earnings per common share (in dollars per share)	$ 0.70	$ 0.80	$ 1.89	$ 1.13
Restricted Stock
Earnings Per Share, Basic and Diluted [Line Items]
Anti-dilutive unvested time restricted stock (in shares)	162,231	48,871	162,231	51,161
Unvested restricted stock
Earnings Per Share, Basic and Diluted [Line Items]
Anti-dilutive unvested time restricted stock (in shares)			967,996	481,567