Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2019	$ 5,116.1	$ 2.6	$ 4,266.9	$ 1,177.9	$ (253.0)	$ (78.3)
Beginning balance, shares at Dec. 31, 2019		257.6
Net income	268.7			268.7
Foreign exchange translation adjustment	(116.6)				(116.6)
Net change in interest rate swaps	(2.7)				(2.7)
Stock-based compensation expense	44.6		44.6
Exercise of options, net of withholding taxes	75.5		75.5
Exercise of options, net of withholding taxes, shares		3.1
Non-cash purchase price consideration	20.1		10.2			9.9
Purchases of common stock	(27.9)					(27.9)
Cash dividends declared	(64.0)		0.2	(64.2)
Ending balance at Jun. 30, 2020	5,313.8	$ 2.6	4,397.4	1,382.4	(372.3)	(96.3)
Ending balance, shares at Jun. 30, 2020		260.7
Beginning balance at Mar. 31, 2020	5,087.6	$ 2.6	4,324.3	1,245.1	(406.1)	(78.3)
Beginning balance, shares at Mar. 31, 2020		259.0
Net income	169.5			169.5
Foreign exchange translation adjustment	34.1				34.1
Net change in interest rate swaps	(0.3)				(0.3)
Stock-based compensation expense	22.1		22.1
Exercise of options, net of withholding taxes	40.7		40.7
Exercise of options, net of withholding taxes, shares		1.7
Non-cash purchase price consideration	20.1		10.2			9.9
Purchases of common stock	(27.9)					(27.9)
Cash dividends declared	(32.1)		0.1	(32.2)
Ending balance at Jun. 30, 2020	5,313.8	$ 2.6	4,397.4	1,382.4	(372.3)	(96.3)
Ending balance, shares at Jun. 30, 2020		260.7
Beginning balance at Dec. 31, 2020	$ 5,716.5	$ 2.6	4,544.0	1,667.0	(201.0)	(296.1)
Beginning balance, shares at Dec. 31, 2020	263.9	263.9
Net income	$ 364.7			364.7
Foreign exchange translation adjustment	10.3				10.3
Net change in interest rate swaps	0.3				0.3
Change in defined benefit plan obligation	0.1				0.1
Stock-based compensation expense	55.5		55.5
Exercise of options, net of withholding taxes	83.3	$ 0.1	83.2
Exercise of options, net of withholding taxes, shares		2.3
Purchases of common stock	(325.0)					(325.0)
Cash dividends declared	(82.0)		0.1	(82.1)
Ending balance at Jun. 30, 2021	$ 5,823.7	$ 2.7	4,682.8	1,949.6	(190.3)	(621.1)
Ending balance, shares at Jun. 30, 2021	266.2	266.2
Beginning balance at Mar. 31, 2021	$ 5,734.2	$ 2.6	4,600.5	1,800.7	(192.1)	(477.5)
Beginning balance, shares at Mar. 31, 2021		264.7
Net income	189.8			189.8
Foreign exchange translation adjustment	1.9				1.9
Net change in interest rate swaps	(0.2)				(0.2)
Change in defined benefit plan obligation	0.1				0.1
Stock-based compensation expense	27.7		27.7
Exercise of options, net of withholding taxes	54.6	$ 0.1	54.5
Exercise of options, net of withholding taxes, shares		1.5
Purchases of common stock	(143.6)					(143.6)
Cash dividends declared	(40.8)		0.1	(40.9)
Ending balance at Jun. 30, 2021	$ 5,823.7	$ 2.7	$ 4,682.8	$ 1,949.6	$ (190.3)	$ (621.1)
Ending balance, shares at Jun. 30, 2021	266.2	266.2