Business Combinations - Summary of Allocation of Purchase Consideration and Estimated Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands					6 Months Ended
	May 07, 2021	Jan. 15, 2021	Aug. 04, 2020	May 27, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Assets acquired
Goodwill					$ 405,223		$ 187,411
Consideration paid
Cash paid, net of cash acquired					197,666	$ 44,265
Contingent consideration					18,775		$ 10,619
xMatters Holdings, Inc
Assets acquired
Accounts receivable	$ 6,716
Other assets	5,433
Property and equipment	1,458
Goodwill	170,037
Total assets acquired	279,324
Liabilities assumed
Accounts payable	1,164
Accrued expenses	5,501
Deferred revenue	34,421
Deferred tax liabilities	3,436
Other liabilities	5,055
Net assets acquired	229,747
Consideration paid
Cash paid	177,800
Cash paid, net of cash acquired					165,265
Fair value of common stock issued	64,482
Total	242,300				229,747
xMatters Holdings, Inc | Acquired Technology
Assets acquired
Intangible assets other than goodwill	8,390
xMatters Holdings, Inc | Trade Names
Assets acquired
Intangible assets other than goodwill	8,200
xMatters Holdings, Inc | Customer Relationships
Assets acquired
Intangible assets other than goodwill	$ 79,090
Red Sky Technologies Inc.
Assets acquired
Accounts receivable		$ 2,926
Other assets		242
Property and equipment		18
Goodwill		49,308
Total assets acquired		78,514
Liabilities assumed
Accounts payable		233
Accrued expenses		773
Deferred revenue		5,866
Deferred tax liabilities		7,048
Other liabilities		26
Net assets acquired		64,568
Consideration paid
Cash paid, net of cash acquired		32,400			32,401
Fair value of common stock issued		23,032
Contingent consideration		9,135
Total		55,400			64,568
Red Sky Technologies Inc. | Acquired Technology
Assets acquired
Intangible assets other than goodwill		3,590
Red Sky Technologies Inc. | Trade Names
Assets acquired
Intangible assets other than goodwill		2,230
Red Sky Technologies Inc. | Customer Relationships
Assets acquired
Intangible assets other than goodwill		$ 20,200
Techwan SA
Assets acquired
Accounts receivable				$ 921
Other assets				254
Goodwill				12,678
Total assets acquired				20,928
Other current assets				235
Liabilities assumed
Accrued expenses				673
Deferred revenue				1,190
Deferred tax liabilities				838
Other current liabilities				927
Net assets acquired				17,300
Consideration paid
Cash paid				9,400
Cash paid, net of cash acquired					9,301
Fair value of common stock issued				5,074
Contingent consideration				2,030
Acquisition-related deferred common stock consideration				895
Total				15,500	17,300
Techwan SA | Acquired Technology
Assets acquired
Intangible assets other than goodwill				1,160
Techwan SA | Trade Names
Assets acquired
Intangible assets other than goodwill				580
Techwan SA | Customer Relationships
Assets acquired
Intangible assets other than goodwill				$ 5,100
SnapComms Limited
Assets acquired
Accounts receivable			$ 1,808
Other assets			943
Property and equipment			118
Goodwill			22,629
Total assets acquired			42,341
Other current assets			283
Liabilities assumed
Accrued expenses			503
Deferred revenue			3,165
Deferred tax liabilities			4,960
Other current liabilities			742
Net assets acquired			32,971
Consideration paid
Cash paid			13,600
Cash paid, net of cash acquired					10,090
Fair value of common stock issued			17,685
Contingent consideration			2,047
Acquisition-related deferred common stock consideration			3,149
Total			34,400		$ 32,971
SnapComms Limited | Acquired Technology
Assets acquired
Intangible assets other than goodwill			2,300
SnapComms Limited | Trade Names
Assets acquired
Intangible assets other than goodwill			960
SnapComms Limited | Customer Relationships
Assets acquired
Intangible assets other than goodwill			$ 13,300