Business Combinations - Consideration (Details) - USD ($) $ in Thousands	1 Months Ended					9 Months Ended	11 Months Ended	12 Months Ended			24 Months Ended
	Jun. 30, 2019	Feb. 28, 2019	Sep. 30, 2018	Aug. 31, 2018	Feb. 28, 2017	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2017
Acquisition
Value of common stock issued and stock awards assumed in acquisition								$ (4,003)	$ 571
Fair value of the pre-combination service through equity awards								182,554
Release of valuation allowance on deferred tax assets								48,000
Goodwill							$ 2,296,784	2,296,784	38,165	$ 17,851	$ 17,851
Other Acquisitions
Acquisition
Consideration transferred								43,200
Amount of purchase price placed into an escrow account								9,100
Acquisition related costs								1,900
Fair value of Class A common stock transferred								12,800
Goodwill							23,425	23,425
Expected tax deductible amount							6,800	6,800
SendGrid
Acquisition
Consideration transferred		$ 2,841,452
Shares issuable as part of acquisition (in shares)		23,600,000
Goodwill, purchase accounting adjustments, net							(4,400)
Acquisition related costs								40,800	13,900
Fair value of Class A common stock transferred		$ 2,658,898
Fair value of the pre-combination service through equity awards		$ 182,554
Release of valuation allowance on deferred tax assets						$ 55,000		47,900
Revenues								177,100
Goodwill							$ 2,235,193	2,235,193
Ytica
Acquisition
Payments to acquire businesses, gross			$ 21,800
Consideration transferred			21,800
Amount of purchase price placed into an escrow account			$ 3,200
Escrow effective period			18 months
Acquisition related costs			$ 600
Goodwill									$ 13,375
Core Network Dynamics Gmbh
Acquisition
Payments to acquire businesses, gross				$ 11,100
Consideration transferred				11,100
Amount of purchase price placed into an escrow account				$ 2,000
Escrow effective period				18 months
Acquisition related costs				$ 800
Goodwill				$ 6,869
Beepsend
Acquisition
Payments to acquire businesses, gross					$ 23,000
Consideration transferred					23,000
Amount of purchase price placed into an escrow account					$ 5,000
Escrow effective period					18 months
Acquisition related costs										$ 300	$ 700
Goodwill					$ 12,837
General and administrative | SendGrid
Acquisition
Acquisition related costs								$ 13,900
Minimum | Other Acquisitions
Acquisition
Escrow effective period	18 months
Maximum | Other Acquisitions
Acquisition
Escrow effective period	36 months
Restricted Stock | Common Class A | Ytica
Acquisition
Shares granted (in shares)			47,574
Aggregate grant value			$ 3,600
Restricted Stock | Common Class A | Core Network Dynamics Gmbh
Acquisition
Shares granted (in shares)				35,950
Aggregate grant value				$ 2,200
Weighted average remaining contractual term				3 years