CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock Issued	Additional Paid-in  Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2021		49.3
Beginning balance at Dec. 31, 2021	$ 1,838.8	$ 0.5	$ 844.1	$ 1,289.1	$ (122.5)	$ (172.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued under share-based compensation plans (in shares)		0.2
Stock issued under share-based compensation plans	0.8		0.8
Share repurchases for tax withholdings	(12.2)		(12.2)
Stock-based compensation expense	23.7		23.7
Unrealized gain (loss) on available-for-sale debt securities	(51.7)				(51.7)
Change in value of redeemable non-controlling interest, net of $3.5 million of tax expense	34.2			34.2
Foreign currency translation	4.3				4.3
Net income	88.5			88.5
Ending balance (in shares) at Mar. 31, 2022		49.4
Ending balance at Mar. 31, 2022	1,926.5	$ 0.5	856.3	1,411.9	(169.9)	(172.3)
Beginning balance (in shares) at Dec. 31, 2021		49.3
Beginning balance at Dec. 31, 2021	1,838.8	$ 0.5	844.1	1,289.1	(122.5)	(172.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of shares of treasury stock	(80.6)
Foreign currency translation	(41.4)
Ending balance (in shares) at Jun. 30, 2022		49.5
Ending balance at Jun. 30, 2022	1,816.4	$ 0.5	880.5	1,446.0	(257.7)	(252.9)
Beginning balance (in shares) at Mar. 31, 2022		49.4
Beginning balance at Mar. 31, 2022	1,926.5	$ 0.5	856.3	1,411.9	(169.9)	(172.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued under share-based compensation plans (in shares)		0.1
Stock issued under share-based compensation plans	2.3		2.3
Share repurchases for tax withholdings	(3.1)		(3.1)
Stock-based compensation expense	24.9		24.9
Unrealized gain (loss) on available-for-sale debt securities	(42.1)				(42.1)
Purchase of shares of treasury stock	(80.6)					(80.6)
Foreign currency translation	(45.7)				(45.7)
Net income	34.1			34.1
Ending balance (in shares) at Jun. 30, 2022		49.5
Ending balance at Jun. 30, 2022	$ 1,816.4	$ 0.5	880.5	1,446.0	(257.7)	(252.9)
Beginning balance (in shares) at Dec. 31, 2022	49.6	49.6
Beginning balance at Dec. 31, 2022	$ 1,649.5	$ 0.5	928.0	1,490.5	(306.3)	(463.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued under share-based compensation plans (in shares)		0.1
Stock issued under share-based compensation plans	6.3		6.3
Share repurchases for tax withholdings	(8.8)		(8.8)
Stock-based compensation expense	25.3		25.3
Unrealized gain (loss) on available-for-sale debt securities	22.2				22.2
Purchase of shares of treasury stock	(92.8)					(92.8)
Foreign currency translation	0.8				0.8
Net income	68.0			68.0
Ending balance (in shares) at Mar. 31, 2023		49.7
Ending balance at Mar. 31, 2023	$ 1,670.5	$ 0.5	950.8	1,558.5	(283.3)	(556.0)
Beginning balance (in shares) at Dec. 31, 2022	49.6	49.6
Beginning balance at Dec. 31, 2022	$ 1,649.5	$ 0.5	928.0	1,490.5	(306.3)	(463.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of shares of treasury stock	(96.0)
Foreign currency translation	$ 6.3
Ending balance (in shares) at Jun. 30, 2023	49.8	49.8
Ending balance at Jun. 30, 2023	$ 1,768.7	$ 0.5	981.3	1,653.8	(307.7)	(559.2)
Beginning balance (in shares) at Mar. 31, 2023		49.7
Beginning balance at Mar. 31, 2023	1,670.5	$ 0.5	950.8	1,558.5	(283.3)	(556.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued under share-based compensation plans (in shares)		0.1
Stock issued under share-based compensation plans	1.2		1.2
Share repurchases for tax withholdings	(6.6)		(6.6)
Stock-based compensation expense	35.9		35.9
Unrealized gain (loss) on available-for-sale debt securities	(29.9)				(29.9)
Purchase of shares of treasury stock	(3.2)				0.0	(3.2)
Foreign currency translation	5.5				5.5
Net income	$ 95.3			95.3
Ending balance (in shares) at Jun. 30, 2023	49.8	49.8
Ending balance at Jun. 30, 2023	$ 1,768.7	$ 0.5	$ 981.3	$ 1,653.8	$ (307.7)	$ (559.2)