Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Basic net income per share:
Consolidated net income		$ 141.1	$ 70.5
Weighted average common shares outstanding (in shares)	42.8	42.6	42.6
Basic net income per share (in dollars per share)	$ 8.64	$ 3.31	$ 1.65
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 369.9	$ 141.1	$ 70.5
Diluted net income per share:
Consolidated net income		$ 141.1	$ 70.5
Weighted average common shares outstanding (in shares)	42.8	42.6	42.6
Net effect of dilutive stock options and restricted stock units (in shares)	0.3	0.3	0.3
Weighted average common shares outstanding for computing diluted income per share (in shares)	43.1	42.9	42.9
Diluted net income per share (in dollars per share)	$ 8.58	$ 3.29	$ 1.64