Consolidated Statements of Stockholders' Deficit - USD ($) $ in Millions	Total	Common Stock Issued	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock at Cost
Beginning balance at Dec. 31, 2022	$ (203.1)	$ 0.9	$ 1,155.2	$ 3,070.6	$ (90.6)	$ (4,339.2)
Beginning balance (in shares) at Dec. 31, 2022						51,700,000
Net income	445.6			445.6
Dividends	(115.9)			(115.9)
Foreign currency translation adjustments	8.7				8.7
Pension and post-retirement liability changes, net of tax	0.2				0.2
Share of equity method investments other comprehensive income	(1.1)				(1.1)
Stock-based compensation expense	23.5		23.5
Change in cash flow hedges, net of tax	3.6				3.6
Treasury shares reissued for common stock	2.9		0.2			$ 2.7
Treasury shares reissued for common stock (in shares)						(100,000)
Treasury stock purchases	(7.1)					$ (7.1)
Ending balance at Sep. 30, 2023	159.5	0.9	1,178.9	3,400.3	(77.0)	$ (4,343.6)
Ending balance (in shares) at Sep. 30, 2023						51,600,000
Beginning balance at Jun. 30, 2023	62.6	0.9	1,169.3	3,309.0	(75.8)	$ (4,340.8)
Beginning balance (in shares) at Jun. 30, 2023						51,700,000
Net income	130.4			130.4
Dividends	(39.1)			(39.1)
Foreign currency translation adjustments	(5.7)				(5.7)
Pension and post-retirement liability changes, net of tax	0.3				0.3
Share of equity method investments other comprehensive income	(1.1)				(1.1)
Stock-based compensation expense	9.7		9.7
Change in cash flow hedges, net of tax	3.1				3.1
Treasury shares reissued for common stock	1.1		(0.1)			$ 1.2
Treasury shares reissued for common stock (in shares)						(100,000)
Treasury stock purchases	(4.0)					$ (4.0)
Ending balance at Sep. 30, 2023	159.5	0.9	1,178.9	3,400.3	(77.0)	$ (4,343.6)
Ending balance (in shares) at Sep. 30, 2023						51,600,000
Beginning balance at Dec. 31, 2023	$ 285.3	0.9	1,184.6	3,506.2	(56.9)	$ (4,349.5)
Beginning balance (in shares) at Dec. 31, 2023	51,588,103					51,600,000
Net income	$ 609.2			609.2
Dividends	(121.4)			(121.4)
Foreign currency translation adjustments	(19.4)				(19.4)
Pension and post-retirement liability changes, net of tax	(0.4)				(0.4)
Share of equity method investments other comprehensive income	(0.2)				(0.2)
Stock-based compensation expense	20.1		20.1
Change in cash flow hedges, net of tax	6.2				6.2
Treasury shares reissued for common stock	3.2					$ 3.0
Treasury shares reissued for common stock (in shares)						(100,000)
Treasury stock purchases	(28.6)					$ (28.6)
Ending balance at Sep. 30, 2024	$ 754.0	0.9	1,204.9	3,994.0	(70.7)	$ (4,375.1)
Ending balance (in shares) at Sep. 30, 2024	51,537,964					51,500,000
Beginning balance at Jun. 30, 2024	$ 577.4	0.9	1,197.9	3,796.0	(60.8)	$ (4,356.6)
Beginning balance (in shares) at Jun. 30, 2024						51,500,000
Net income	239.0			239.0
Dividends	(41.0)			(41.0)
Foreign currency translation adjustments	(9.9)				(9.9)
Pension and post-retirement liability changes, net of tax	0.2				0.2
Share of equity method investments other comprehensive income	(0.2)				(0.2)
Stock-based compensation expense	6.8		6.8
Treasury shares reissued for common stock	1.1		0.2			$ 0.9
Treasury stock purchases	(19.4)					(19.4)
Ending balance at Sep. 30, 2024	$ 754.0	$ 0.9	$ 1,204.9	$ 3,994.0	$ (70.7)	$ (4,375.1)
Ending balance (in shares) at Sep. 30, 2024	51,537,964					51,500,000