Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Feb. 06, 2020	Dec. 31, 2019	Oct. 04, 2019	Oct. 01, 2019	Aug. 21, 2019	May 24, 2019	Apr. 18, 2019
Assets Acquired
Operating lease right-of-use asset	$ 13,598		$ 8,056
Goodwill	$ 379,486		346,134
Customer relationships
Assets Acquired
Intangible assets			$ 1,100
Localytics
Assets Acquired
Cash		$ 0
Accounts receivable		3,648
Other current assets		6,325
Tax credits receivable		0
Operating lease right-of-use asset		7,605
Property and equipment		409
Goodwill		40,109
Other assets		6
Total assets acquired		95,502
Liabilities Assumed
Accounts payable		(2,382)
Accrued expense and other		(6,752)
Deferred tax liabilities		(4,721)
Deferred revenue		(4,812)
Operating lease liabilities		(7,835)
Total liabilities assumed		(26,502)
Total consideration		69,000
Localytics | Customer relationships
Assets Acquired
Intangible assets		30,500
Localytics | Trade name
Assets Acquired
Intangible assets		300
Localytics | Technology
Assets Acquired
Intangible assets		$ 6,600
Altify
Assets Acquired
Cash				$ 730
Accounts receivable				6,629
Other current assets				889
Tax credits receivable				916
Operating lease right-of-use asset				1,085
Property and equipment				139
Goodwill				34,426
Other assets				378
Total assets acquired				104,906
Liabilities Assumed
Accounts payable				(1,499)
Accrued expense and other				(3,901)
Deferred tax liabilities				(7,083)
Deferred revenue				(7,907)
Operating lease liabilities				(516)
Total liabilities assumed				(20,906)
Total consideration				84,000
Altify | Customer relationships
Assets Acquired
Intangible assets				50,954
Altify | Trade name
Assets Acquired
Intangible assets				1,112
Altify | Technology
Assets Acquired
Intangible assets				$ 7,648
InGenius
Assets Acquired
Cash					$ 11
Accounts receivable					1,456
Other current assets					317
Tax credits receivable					1,489
Operating lease right-of-use asset					1,099
Property and equipment					364
Goodwill					24,141
Other assets					0
Total assets acquired					45,085
Liabilities Assumed
Accounts payable					(128)
Accrued expense and other					(2,807)
Deferred tax liabilities					(4,897)
Deferred revenue					(2,960)
Operating lease liabilities					0
Total liabilities assumed					(10,792)
Total consideration					34,293
InGenius | Customer relationships
Assets Acquired
Intangible assets					11,208
InGenius | Trade name
Assets Acquired
Intangible assets					424
InGenius | Technology
Assets Acquired
Intangible assets					$ 4,576
Cimpl
Assets Acquired
Cash						$ 142
Accounts receivable						1,041
Other current assets						278
Tax credits receivable						1,383
Operating lease right-of-use asset						230
Property and equipment						233
Goodwill						12,928
Other assets						6
Total assets acquired						32,127
Liabilities Assumed
Accounts payable						(305)
Accrued expense and other						(1,206)
Deferred tax liabilities						(4,595)
Deferred revenue						(350)
Operating lease liabilities						0
Total liabilities assumed						(6,456)
Total consideration						25,671
Cimpl | Customer relationships
Assets Acquired
Intangible assets						12,430
Cimpl | Trade name
Assets Acquired
Intangible assets						216
Cimpl | Technology
Assets Acquired
Intangible assets						$ 3,240
Kapost
Assets Acquired
Cash							$ 0
Accounts receivable							3,901
Other current assets							1,066
Tax credits receivable							0
Operating lease right-of-use asset							2,136
Property and equipment							686
Goodwill							20,953
Other assets							0
Total assets acquired							59,020
Liabilities Assumed
Accounts payable							(50)
Accrued expense and other							(3,724)
Deferred tax liabilities							(1,954)
Deferred revenue							(3,893)
Operating lease liabilities							0
Total liabilities assumed							(9,621)
Total consideration							49,399
Kapost | Customer relationships
Assets Acquired
Intangible assets							23,735
Kapost | Trade name
Assets Acquired
Intangible assets							787
Kapost | Technology
Assets Acquired
Intangible assets							$ 5,756
Postup
Assets Acquired
Cash								$ 19
Accounts receivable								1,054
Other current assets								1,373
Tax credits receivable								0
Operating lease right-of-use asset								0
Property and equipment								743
Goodwill								21,973
Other assets								0
Total assets acquired								39,240
Liabilities Assumed
Accounts payable								(447)
Accrued expense and other								(530)
Deferred tax liabilities								(3,248)
Deferred revenue								(15)
Operating lease liabilities								0
Total liabilities assumed								(4,240)
Total consideration								35,000
Postup | Customer relationships
Assets Acquired
Intangible assets								10,667
Postup | Trade name
Assets Acquired
Intangible assets								468
Postup | Technology
Assets Acquired
Intangible assets								$ 2,943