Acquisitions - Assets Acquired and Liabilities Assumed and Divested (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Oct. 04, 2019	Aug. 21, 2019	May 24, 2019	Apr. 18, 2019
Assets Acquired
Operating lease right-of-use asset	$ 12,353	$ 8,056
Goodwill	377,745	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				39,646
Other assets				6
Total assets acquired				95,039
Liabilities Assumed
Accounts payable				(2,382)
Accrued expense and other				(6,752)
Deferred tax liabilities				(4,258)
Deferred revenue				(4,812)
Operating lease liabilities				(7,835)
Total liabilities assumed				(26,039)
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 Ireland Limited
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	$ 154,100			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 Ireland Limited | Customer relationships
Assets Acquired
Intangible assets				50,954
Altify Ireland Limited | Trade name
Assets Acquired
Intangible assets				1,112
Altify Ireland Limited | Technology
Assets Acquired
Intangible assets				7,648
InGenius Software Inc.
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 Software Inc. | Customer relationships
Assets Acquired
Intangible assets				11,208
InGenius Software Inc. | Trade name
Assets Acquired
Intangible assets				424
InGenius Software Inc. | 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