Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Beginning balance, value at Dec. 31, 2021	$ 893.7	$ 0.6	$ 465.6	$ 915.6		$ (488.1)
Beginning balance, shares at Dec. 31, 2021		62.3				4.3
Vesting of restricted stock, shares		0.2
Stock-based compensation	111.0		111.0
Repurchases of common stock	(99.8)					$ (99.8)
Repurchases of common stock, shares						0.4
Net income	281.4			281.4
Other comprehensive earnings (loss), net of tax	(3.7)				$ (3.7)
Ending balance, value at Dec. 31, 2022	1,182.6	$ 0.6	576.6	1,197.0	(3.7)	$ (587.9)
Ending balance, shares at Dec. 31, 2022		62.5				4.7
Vesting of restricted stock, shares		0.2
Stock-based compensation	147.8		147.8
Dividends declared	(67.8)			(67.8)
Repurchases of common stock	(303.1)					$ (303.1)
Repurchases of common stock, shares						1.4
Net income	340.8			340.8
Other comprehensive earnings (loss), net of tax	2.7				2.7
Ending balance, value at Dec. 31, 2023	1,303.0	$ 0.6	724.4	1,470.0	(1.0)	$ (891.0)
Ending balance, shares at Dec. 31, 2023		62.7				6.1
Vesting of restricted stock, shares		0.3
Stock-based compensation	0.4		0.4
Dividends declared	(84.5)			(84.5)
Repurchases of common stock	(145.4)					$ (145.4)
Repurchases of common stock, shares						1.0
Net income	502.0			502.0
Other comprehensive earnings (loss), net of tax	0.4				0.4
Ending balance, value at Dec. 31, 2024	$ 1,575.9	$ 0.6	$ 724.8	$ 1,887.5	$ (0.6)	$ (1,036.4)
Ending balance, shares at Dec. 31, 2024		63.0				7.1