Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 557,054	$ 478,035	$ 298,373
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	478,389	440,674	434,520
Stock-based compensation	197,411	187,140	183,813
(Benefit) provision for deferred income taxes	(33,821)	933	2,339
Amortization of debt discount and issuance costs	62,823	45,857	41,958
Other non-cash reconciling items, net	23,027	8,528	17,018
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(90,381)	(64,471)	(30,445)
Prepaid expenses and other current assets	(25,395)	11,689	(4,132)
Accounts payable and accrued expenses	39,211	8,769	42,238
Deferred revenue	(1,318)	(13,547)	(919)
Other current liabilities	18,101	(17,230)	9,422
Other non-current assets and liabilities	(10,101)	(28,073)	14,142
Net cash provided by operating activities	1,215,000	1,058,304	1,008,327
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(127,999)	(165,329)	(79)
Cash paid for asset acquisition	(36,376)	0	0
Cash paid for equity method investment	0	(36,008)	0
Purchases of property and equipment	(514,313)	(359,667)	(217,609)
Capitalization of internal-use software development costs	(217,559)	(202,410)	(188,132)
Purchases of short-and long-term marketable securities	(1,782,849)	(1,990,148)	(873,697)
Proceeds from sales of short-and long-term marketable securities	30,350	856	16,569
Proceeds from maturities of short-and long-term marketable securities	1,597,651	1,084,373	758,481
Other non-current assets and liabilities	8,121	399	(2,066)
Net cash used in investing activities	(1,042,974)	(1,667,934)	(506,533)
Cash flows from financing activities:
Proceeds from the issuance of convertible senior notes	0	1,135,629	1,132,185
Proceeds from the issuance of warrants	0	185,150	119,945
Purchase of note hedge related to convertible senior notes	0	(312,225)	(261,740)
Repayment of convertible senior notes	0	(690,000)	0
Proceeds related to the issuance of common stock under stock plans	59,775	57,112	62,608
Employee taxes paid related to net share settlement of stock-based awards	(89,828)	(75,266)	(64,305)
Repurchases of common stock	(193,588)	(334,519)	(750,000)
Other non-current assets and liabilities	0	(1,558)	(5,085)
Net cash (used in) provided by financing activities	(223,641)	(35,677)	233,608
Effects of exchange rate changes on cash, cash equivalents and restricted cash	10,935	2,466	(12,844)
Net (decrease) increase in cash, cash equivalents and restricted cash	(40,680)	(642,841)	722,558
Cash, cash equivalents and restricted cash at beginning of year	394,146	1,036,987	314,429
Cash, cash equivalents and restricted cash at end of year	353,466	394,146	1,036,987
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds received in the years ended December 31, 2020, 2019 and 2018 of $17,491, $3,731 and $18,501, respectively	79,163	73,898	45,129
Cash paid for interest expense	5,954	1,438	639
Cash paid for operating lease liabilities	201,856	153,818
Non-cash activities:
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	200,735	529,376
Purchases of property and equipment and capitalization of internal-use software development costs included in accounts payable and accrued expenses	75,666	88,238	54,867
Capitalization of stock-based compensation	$ 38,333	$ 35,905	$ 34,785