Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 443,684	$ 358,935
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	350,681	324,874
Stock-based compensation	146,901	140,262
(Benefit) provision for deferred income taxes	(22,548)	24,581
Amortization of debt discount and issuance costs	47,057	30,761
Other non-cash reconciling items, net	16,284	3,778
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(85,439)	(38,144)
Prepaid expenses and other current assets	(21,380)	(11,663)
Accounts payable and accrued expenses	49,818	(29,441)
Deferred revenue	14,803	16,714
Other current liabilities	(1,638)	(21,850)
Other non-current assets and liabilities	(14,316)	(22,643)
Net cash provided by operating activities	923,907	776,164
Cash flows from investing activities:
Cash received (paid) for business acquisitions, net of cash acquired	106	(121,409)
Cash paid for asset acquisition	(36,376)	0
Cash paid for equity method investment	0	(36,008)
Purchases of property and equipment	(395,793)	(268,766)
Capitalization of internal-use software development costs	(168,634)	(159,645)
Purchases of short- and long-term marketable securities	(1,153,526)	(1,373,563)
Proceeds from sales of short- and long-term marketable securities	29,809	547
Proceeds from maturities of short- and long-term marketable securities	1,301,354	878,779
Other non-current assets and liabilities	(1,980)	1,895
Net cash used in investing activities	(425,040)	(1,078,170)
Cash flows from financing activities:
Proceeds from the issuance of convertible senior notes	0	1,135,629
Proceeds from the issuance of warrants	0	185,150
Purchase of note hedge related to convertible senior notes	0	(312,225)
Repayment of convertible senior notes	0	(690,000)
Proceeds related to the issuance of common stock under stock plans	45,812	43,204
Employee taxes paid related to net share settlement of stock-based awards	(77,299)	(61,116)
Repurchases of common stock	(121,078)	(291,788)
Other non-current assets and liabilities	0	(1,558)
Net cash (used in) provided by financing activities	(152,565)	7,296
Effects of exchange rate changes on cash, cash equivalents and restricted cash	3,535	(2,650)
Net increase (decrease) in cash, cash equivalents and restricted cash	349,837	(297,360)
Cash, cash equivalents and restricted cash at beginning of period	394,146	1,036,987
Cash, cash equivalents and restricted cash at end of period	743,983	739,627
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds received of $16,674 and $2,746 for the nine months ended September 30, 2020 and 2019, respectively	31,634	65,896
Cash paid for interest expense	5,235	719
Cash paid for operating lease liabilities	144,322	107,478
Non-cash activities:
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	128,177	87,207
Purchases of property and equipment and capitalization of internal-use software development costs included in accounts payable and accrued expenses	48,357	64,982
Capitalization of stock-based compensation	28,487	27,352
Proceeds from income tax refunds	$ 16,674	$ 2,746