Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Par	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2022	$ 1,554.2	$ 1.1	$ 905.0	$ 2,104.9	$ (174.4)	$ (1,282.4)
Increase (Decrease) in Stockholders' Equity
Net income	42.7			42.7
Dividends paid on common stock	(10.4)			(10.4)
Change in other comprehensive income - net of tax	22.3				22.3
Stock-based activity	13.4		15.8			(2.4)
Ending Balance at Mar. 31, 2023	1,622.2	1.1	920.8	2,137.2	(152.1)	(1,284.8)
Beginning Balance at Dec. 31, 2022	1,554.2	1.1	905.0	2,104.9	(174.4)	(1,282.4)
Increase (Decrease) in Stockholders' Equity
Net income	85.2
Change in other comprehensive income - net of tax	29.2
Ending Balance at Jun. 30, 2023	1,666.1	1.1	925.9	2,169.2	(145.2)	(1,284.9)
Beginning Balance at Mar. 31, 2023	1,622.2	1.1	920.8	2,137.2	(152.1)	(1,284.8)
Increase (Decrease) in Stockholders' Equity
Net income	42.5			42.5
Dividends paid on common stock	(10.5)			(10.5)
Change in other comprehensive income - net of tax	6.9				6.9
Stock-based activity	5.0		5.1			(0.1)
Ending Balance at Jun. 30, 2023	1,666.1	1.1	925.9	2,169.2	(145.2)	(1,284.9)
Beginning Balance at Dec. 31, 2023	1,716.5	1.1	936.8	2,168.7	(74.1)	(1,316.0)
Increase (Decrease) in Stockholders' Equity
Net income	36.5			36.5
Dividends paid on common stock	(12.6)			(12.6)
Repurchases of common stock	(100.7)					(100.7)
Change in other comprehensive income - net of tax	(14.9)				(14.9)
Stock-based activity	7.3		17.8			(10.5)
Ending Balance at Mar. 31, 2024	1,632.1	1.1	954.6	2,192.6	(89.0)	(1,427.2)
Beginning Balance at Dec. 31, 2023	1,716.5	1.1	936.8	2,168.7	(74.1)	(1,316.0)
Increase (Decrease) in Stockholders' Equity
Net income	86.5
Change in other comprehensive income - net of tax	(17.2)				(17.2)
Ending Balance at Jun. 30, 2024	1,571.2	1.1	959.6	2,230.2	(91.3)	(1,528.4)
Beginning Balance at Mar. 31, 2024	1,632.1	1.1	954.6	2,192.6	(89.0)	(1,427.2)
Increase (Decrease) in Stockholders' Equity
Net income	50.0			50.0
Dividends paid on common stock	(12.4)			(12.4)
Repurchases of common stock	(101.1)					(101.1)
Change in other comprehensive income - net of tax	(2.3)				(2.3)
Stock-based activity	4.9		5.0			(0.1)
Ending Balance at Jun. 30, 2024	$ 1,571.2	$ 1.1	$ 959.6	$ 2,230.2	$ (91.3)	$ (1,528.4)