Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net Income (Loss) Attributable to Parent	$ 74.3	$ 77.4
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	(1.4)	0.0
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	(1.4)	0.0
Net Income (Loss) Available to Common Stockholders, Basic	72.9	77.4
Net Income (Loss) Available to Common Stockholders, Diluted	$ 72.9	$ 77.4
Denominator:
Denominator for basic earnings per share — weighted average shares	35,800	35,300
Basic earnings per share from consolidated operations (in dollars per share)	$ 2.04	$ 2.19
Effect of dilutive securities:
Equity compensation plans	100	500
Weighted-average shares outstanding - diluted	35,900	35,800
Diluted earnings per share (in dollars per share)	$ 2.03	$ 2.16