Unaudited Condensed Consolidated Statement Of Shareholders' Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock
BALANCE at period start (in shares) at Dec. 31, 2024			63,562,149
BALANCE at period start at Dec. 31, 2024	$ 2,457.3		$ 0.6	$ 20.3	$ 5,331.8		$ (2,895.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	175.5				175.5
Repurchases of common stock, including excise tax	(226.6)						(226.6)
Stock-based compensation expense	16.7			16.7
Shares awarded under stock-based compensation plans, net of shares withheld for taxes	(19.7)			(33.7)	(4.8)		18.8
BALANCE at period end (in shares) at Mar. 31, 2025			63,562,149
BALANCE at period end at Mar. 31, 2025	2,403.2		$ 0.6	3.3	5,502.5		(3,103.2)
BALANCE at period start (in shares) at Dec. 31, 2025			63,562,149
BALANCE at period start at Dec. 31, 2025	2,341.1	$ (10.5)	$ 0.6	32.0	5,976.1	$ (10.5)	(3,667.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	205.4				205.4
Repurchases of common stock, including excise tax	(302.6)						(302.6)
Stock-based compensation expense	17.3			17.3
Shares awarded under stock-based compensation plans, net of shares withheld for taxes	(23.8)			(42.3)			18.5
BALANCE at period end (in shares) at Mar. 31, 2026			63,562,149
BALANCE at period end at Mar. 31, 2026	$ 2,226.9		$ 0.6	$ 7.0	$ 6,171.0		$ (3,951.7)