Business Combinations - Purchase Price Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Feb. 28, 2019	Feb. 01, 2019	Dec. 31, 2018	Sep. 30, 2018	Aug. 31, 2018	Dec. 31, 2017	Feb. 28, 2017
Acquisition
Goodwill	$ 2,296,784			$ 38,165			$ 17,851
Other Acquisitions
Acquisition
Net liabilities	(3,219)
Intangible assets	22,986
Goodwill	23,425
Total purchase price	43,192
SendGrid
Acquisition
Cash and cash equivalents	156,783
Accounts receivable and other current assets	11,635
Property and equipment, net	38,350
Operating right of use asset	33,742		$ 33,700
Intangible assets	483,000
Other assets	1,664
Goodwill	2,235,193
Accounts payable and other liabilities	11,114
Operating lease liability	(32,568)		(32,600)
Financing lease liability	(13,616)		$ (13,600)
Note payable	(5,387)
Deferred tax liability	(56,230)	$ (56,200)
Total purchase price	2,841,452
Ytica
Acquisition
Net liabilities				(1,538)
Intangible assets				9,920
Goodwill				13,375
Deferred tax liability					$ (1,700)
Total purchase price				21,757
Core Network Dynamics Gmbh
Acquisition
Net liabilities						$ (313)
Intangible assets						4,500
Goodwill						6,869
Deferred tax liability						(1,200)
Total purchase price						11,056
Beepsend
Acquisition
Net liabilities								$ (3,575)
Intangible assets								13,700
Goodwill								12,837
Deferred tax liability								(2,600)
Total purchase price								22,962
Developed technology | Other Acquisitions
Acquisition
Intangible assets	11,771
Developed technology | SendGrid
Acquisition
Intangible assets	$ 294,000
Developed technology | Ytica
Acquisition
Intangible assets				$ 9,090
Developed technology | Core Network Dynamics Gmbh
Acquisition
Intangible assets						$ 3,910
Developed technology | Beepsend
Acquisition
Intangible assets								$ 5,000