Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income	$ 155,695	$ 123,146
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	131,471	116,208
Stock-based compensation	54,305	47,493
Provision (benefit) for deferred income taxes	1,764	(2,888)
Amortization of debt discount and issuance costs	16,257	15,633
Other non-cash reconciling items, net	1,226	12,052
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(15,580)	(73,913)
Prepaid expenses and other current assets	(35,388)	(10,434)
Accounts payable and accrued expenses	(72,986)	(27,458)
Deferred revenue	25,439	26,989
Other current liabilities	(716)	928
Other non-current assets and liabilities	(11,694)	(4,513)
Net cash provided by operating activities	249,793	223,243
Cash flows from investing activities:
Cash (paid) received for business acquisitions, net of cash acquired	(15,638)	106
Cash paid for asset acquisition	0	(36,376)
Purchases of property and equipment	(87,222)	(141,095)
Capitalization of internal-use software development costs	(77,497)	(74,334)
Purchases of short- and long-term marketable securities	(90,279)	(389,779)
Proceeds from sales of short- and long-term marketable securities	7,154	1,179
Proceeds from maturities of short- and long-term marketable securities	226,995	529,637
Other non-current assets and liabilities	179	(76)
Net cash used in investing activities	(36,308)	(110,738)
Cash flows from financing activities:
Proceeds related to the issuance of common stock under stock plans	21,410	19,546
Employee taxes paid related to net share settlement of stock-based awards	(63,946)	(50,835)
Repurchases of common stock	(58,241)	(80,550)
Net cash used in financing activities	(100,777)	(111,839)
Effects of exchange rate changes on cash, cash equivalents and restricted cash	(7,151)	(8,983)
Net increase (decrease) in cash, cash equivalents and restricted cash	105,557	(8,317)
Cash, cash equivalents and restricted cash at beginning of period	353,466	394,146
Cash, cash equivalents and restricted cash at end of period	459,023	385,829
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds received of $1,846 and $1,204 for the three months ended March 31, 2021 and 2020, respectively	17,736	21,440
Cash paid for interest expense	2,156	2,360
Cash paid for operating lease liabilities	63,673	47,066
Non-cash activities:
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	82,125	31,050
Purchases of property and equipment and capitalization of internal-use software development costs included in accounts payable and accrued expenses	60,193	22,874
Capitalization of stock-based compensation	$ 9,459	$ 8,722