CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 860,333	$ 792,845	$ 2,555,865	$ 2,351,862
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)	316,866	283,439	943,553	828,825
Research and development	82,899	66,773	242,199	202,087
Sales and marketing	108,514	122,749	336,762	370,004
General and administrative	134,265	128,365	405,275	385,435
Amortization of acquired intangible assets	11,959	10,340	35,446	31,155
Restructuring charge	565	21	5,567	10,439
Total costs and operating expenses	655,068	611,687	1,968,802	1,827,945
Income from operations	205,265	181,158	587,063	523,917
Interest income	2,872	6,307	12,186	22,852
Interest expense	(18,144)	(17,324)	(54,015)	(51,778)
Other income (expense), net	3,635	(2,158)	2,007	(7,869)
Income before provision for income taxes	193,628	167,983	547,241	487,122
Provision for income taxes	(13,648)	(8,801)	(43,555)	(41,764)
Loss from equity method investment	(1,064)	(559)	(12,578)	(1,674)
Net income	$ 178,916	$ 158,623	$ 491,108	$ 443,684
Net income per share:
Basic (in dollars per share)	$ 1.10	$ 0.97	$ 3.01	$ 2.73
Diluted (in dollars per share)	$ 1.08	$ 0.95	$ 2.96	$ 2.69
Shares used in per share calculations:
Basic (in shares)	162,767	162,757	162,967	162,387
Diluted (in shares)	166,318	166,519	166,090	164,990