CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDER'S EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-in Capital	Retained Earnings	Other
Common Stock, Shares		51.8
Total stockholders’ equity at Dec. 31, 2021	$ 1,865.4	$ 0.5	$ 690.8	$ 1,174.4	$ (0.3)
Stock-based compensation expense	24.0		24.0
Employee stock purchase plan, shares		0.2
Employee stock purchase plan, value	10.4		10.4
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(11.3)		(11.3)
Vesting of restricted stock units, shares		0.0
Stock Repurchased and Retired During Period, Shares		(1.6)
Stock Repurchased and Retired During Period, Value	(170.0)		(21.8)	(148.2)
Foreign currency translation adjustments	(1.7)				(1.7)
Net income	139.3			139.3
Shares Outstanding at Jun. 30, 2022		50.4
Total stockholders’ equity at Jun. 30, 2022	1,856.1	$ 0.5	692.1	1,165.5	(2.0)
Common Stock, Shares		51.3
Total stockholders’ equity at Mar. 31, 2022	1,869.2	$ 0.5	696.0	1,173.0	(0.3)
Stock-based compensation expense	11.2		11.2
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(2.5)		(2.5)
Vesting of restricted stock units, shares		0.0
Stock Repurchased and Retired During Period, Shares		(0.9)
Stock Repurchased and Retired During Period, Value	(92.6)		(12.6)	(80.0)
Foreign currency translation adjustments	(1.7)				(1.7)
Net income	72.5			72.5
Shares Outstanding at Jun. 30, 2022		50.4
Total stockholders’ equity at Jun. 30, 2022	1,856.1	$ 0.5	692.1	1,165.5	(2.0)
Total stockholders’ equity at Dec. 31, 2022	1,901.3	$ 0.5	703.5	1,200.0	(2.7)
Stock-based compensation expense	23.4		23.4
Employee stock purchase plan, shares		0.4
Employee stock purchase plan, value	11.1		11.1
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(14.2)		(14.2)
Vesting of restricted stock units, shares		0.0
Stock Repurchased and Retired During Period, Shares		(1.4)
Stock Repurchased and Retired During Period, Value	(107.0)		(21.0)	(86.0)
Foreign currency translation adjustments	2.4				2.4
Net income	109.6			109.6
Shares Outstanding at Jun. 30, 2023		48.5
Total stockholders’ equity at Jun. 30, 2023	1,926.6	$ 0.5	702.8	1,223.6	(0.3)
Common Stock, Shares		49.2
Total stockholders’ equity at Mar. 31, 2023	1,923.5	$ 0.5	714.4	1,210.3	(1.7)
Stock-based compensation expense	11.3		11.3
Employee stock purchase plan, shares		0.2
Employee stock purchase plan, value	0.0		0.0
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(10.0)		(10.0)
Vesting of restricted stock units, shares		0.0
Stock Repurchased and Retired During Period, Shares		(0.9)
Stock Repurchased and Retired During Period, Value	(59.7)		(12.9)	(46.8)
Foreign currency translation adjustments	1.4				1.4
Net income	60.1			60.1
Shares Outstanding at Jun. 30, 2023		48.5
Total stockholders’ equity at Jun. 30, 2023	$ 1,926.6	$ 0.5	$ 702.8	$ 1,223.6	$ (0.3)