Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net Income (Loss) Attributable to Parent	$ 89.0	$ 52.5	$ 207.7	$ 193.2
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	(1.5)	(0.9)	(3.7)	(3.7)
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	(1.5)	(0.9)	(3.7)	(3.7)
Net Income (Loss) Available to Common Stockholders, Basic	87.5	51.6	204.0	189.5
Net Income (Loss) Available to Common Stockholders, Diluted	$ 87.5	$ 51.6	$ 204.0	$ 189.5
Denominator:
Denominator for basic earnings per share — weighted average shares	35,800	35,700	35,800	35,600
Basic earnings per share from consolidated operations (in dollars per share)	$ 2.44	$ 1.44	$ 5.70	$ 5.32
Effect of dilutive securities:
Equity compensation plans	100	100	100	100
Weighted-average shares outstanding - diluted	35,900	35,800	35,900	35,700
Diluted earnings per share (in dollars per share)	$ 2.43	$ 1.44	$ 5.68	$ 5.30