Nature of Business and Basis of Presentation (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) country server $ / shares	Jun. 30, 2017 USD ($) $ / shares	Jun. 30, 2018 USD ($) segment country server $ / shares	Jun. 30, 2017 USD ($) $ / shares	Dec. 31, 2017 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of servers (more than) | server	200,000		200,000
Number of countries in which servers are located | country	130		130
Number of industry segments | segment			1
Current assets:
Accounts receivable	$ 479,865		$ 479,865		$ 461,457
Prepaid expenses and other current assets	147,324		147,324		172,853
Total current assets	2,484,160		2,484,160		1,346,246
Deferred income tax assets	44,230		44,230		36,231
Other assets	132,373		132,373		136,365
Total assets	5,604,704		5,604,704		4,648,916
Current liabilities:
Deferred revenue	100,314		100,314		70,495
Total current liabilities	1,136,328		1,136,328		456,694
Deferred revenue	6,075		6,075		6,062
Deferred income tax liabilities	18,236		18,236		17,823
Total liabilities	2,159,426		2,159,426		1,286,447
Stockholders’ equity:
Accumulated deficit	(632,489)		(632,489)		(690,662)
Total stockholders’ equity	3,445,278		3,445,278		3,362,469
Total liabilities and stockholders’ equity	5,604,704		5,604,704		4,648,916
Revenue	662,759	$ 605,832	1,331,483	$ 1,206,125
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)	235,487	214,680	470,312	420,407
Sales and marketing	131,680	117,944	254,233	232,436
Total costs and operating expenses	605,642	520,239	1,205,809	1,015,198
Income from operations	57,117	85,593	125,674	190,927
Income before provision for income taxes	51,553	85,791	119,246	190,468
Provision for income taxes	$ 8,492	$ 29,039	$ 22,471	$ 59,133
Net income per share:
Basic (in dollars per share) | $ / shares	$ 0.25	$ 0.33	$ 0.57	$ 0.76
Diluted (in dollars per share) | $ / shares	$ 0.25	$ 0.33	$ 0.56	$ 0.75
Comprehensive income	$ 19,424	$ 70,640	$ 76,735	$ 155,960
Cash flows from operating activities:
Net income	43,061	56,752	96,775	131,335
Adjustments to reconcile net income to net cash provided by operating activities:
(Benefit) provision for deferred income taxes			(12,116)	35,223
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable			(16,889)	(4,265)
Prepaid expenses and other current assets			8,578	(51,224)
Deferred revenue			29,552	9,811
Other non-current assets and liabilities			59	(8,835)
Net cash provided by operating activities			411,691	367,251
Cash flows from investing activities:
Other non-current assets and liabilities			(479)	(1,143)
Net cash used in investing activities			(529,587)	(154,633)
Effects of exchange rate changes on cash, cash equivalents and restricted cash			(11,460)	10,252
Net increase in cash, and cash equivalents and restricted cash			663,910	28,501
Cash, cash equivalents and restricted cash at beginning of period			314,429	324,626
Cash, cash equivalents and restricted cash at end of period	$ 978,339	353,127	$ 978,339	353,127
Prepaid and other current assets | Intra-Entity Asset Transfers
Cash flows from investing activities:
Cumulative-effect adjustment					11,600
Deferred costs included in other assets | Intra-Entity Asset Transfers
Cash flows from investing activities:
Cumulative-effect adjustment					27,000
As Previously Reported
Current assets:
Accounts receivable					459,127
Prepaid expenses and other current assets					137,809
Total current assets					1,308,872
Deferred income tax assets					51,069
Other assets					112,829
Total assets					4,602,844
Current liabilities:
Deferred revenue					77,705
Total current liabilities					463,904
Deferred revenue					6,839
Deferred income tax liabilities					15,510
Total liabilities					1,292,121
Stockholders’ equity:
Accumulated deficit					(742,408)
Total stockholders’ equity					3,310,723
Total liabilities and stockholders’ equity					4,602,844
Revenue		608,908		1,218,145
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)		214,650		420,353
Sales and marketing		119,432		232,998
Total costs and operating expenses		521,697		1,015,706
Income from operations		87,211		202,439
Income before provision for income taxes		87,409		201,980
Provision for income taxes		$ 29,637		$ 63,278
Net income per share:
Basic (in dollars per share) | $ / shares		$ 0.33		$ 0.80
Diluted (in dollars per share) | $ / shares		$ 0.33		$ 0.80
Cash flows from operating activities:
Net income		$ 57,772		$ 138,702
Adjustments to reconcile net income to net cash provided by operating activities:
(Benefit) provision for deferred income taxes				39,368
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable				(17,873)
Prepaid expenses and other current assets				(50,108)
Deferred revenue				10,406
Other non-current assets and liabilities				(8,450)
Net cash provided by operating activities				367,251
Cash flows from investing activities:
Other non-current assets and liabilities				(1,249)
Net cash used in investing activities				(154,739)
Effects of exchange rate changes on cash, cash equivalents and restricted cash				10,189
Net increase in cash, and cash equivalents and restricted cash				28,332
Cash, cash equivalents and restricted cash at beginning of period				324,169
Cash, cash equivalents and restricted cash at end of period		352,501		352,501
Adjustments | Accounting Standards Update 2014-09
Current assets:
Accounts receivable					2,330
Prepaid expenses and other current assets					35,044
Total current assets					37,374
Deferred income tax assets					(14,838)
Other assets					23,536
Total assets					46,072
Current liabilities:
Deferred revenue					(7,210)
Total current liabilities					(7,210)
Deferred revenue					(777)
Deferred income tax liabilities					2,313
Total liabilities					(5,674)
Stockholders’ equity:
Accumulated deficit					51,746
Total stockholders’ equity					51,746
Total liabilities and stockholders’ equity					$ 46,072
Revenue		(3,076)		(12,020)
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)		30		54
Sales and marketing		(1,488)		(562)
Total costs and operating expenses		(1,458)		(508)
Income from operations		(1,618)		(11,512)
Income before provision for income taxes		(1,618)		(11,512)
Provision for income taxes		$ (598)		$ (4,145)
Net income per share:
Basic (in dollars per share) | $ / shares		$ 0.00		$ (0.04)
Diluted (in dollars per share) | $ / shares		$ 0.00		$ (0.05)
Comprehensive income		$ 1,000		$ 7,400
Cash flows from operating activities:
Net income		(1,020)		(7,367)
Adjustments to reconcile net income to net cash provided by operating activities:
(Benefit) provision for deferred income taxes				(4,145)
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable				13,608
Prepaid expenses and other current assets				(1,116)
Deferred revenue				(595)
Other non-current assets and liabilities				(385)
Net cash provided by operating activities				0
Cash flows from investing activities:
Other non-current assets and liabilities				0
Net cash used in investing activities				0
Effects of exchange rate changes on cash, cash equivalents and restricted cash				0
Net increase in cash, and cash equivalents and restricted cash				0
Cash, cash equivalents and restricted cash at beginning of period				0
Cash, cash equivalents and restricted cash at end of period		0		0
Adjustments | Accounting Standards Update 2016-18
Cash flows from operating activities:
Net income				0
Adjustments to reconcile net income to net cash provided by operating activities:
(Benefit) provision for deferred income taxes				0
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable				0
Prepaid expenses and other current assets				0
Deferred revenue				0
Other non-current assets and liabilities				0
Net cash provided by operating activities				0
Cash flows from investing activities:
Other non-current assets and liabilities				106
Net cash used in investing activities				106
Effects of exchange rate changes on cash, cash equivalents and restricted cash				63
Net increase in cash, and cash equivalents and restricted cash				169
Cash, cash equivalents and restricted cash at beginning of period				457
Cash, cash equivalents and restricted cash at end of period		$ 626		$ 626