Business Combinations - Summary of Allocation of Purchase Consideration and Estimated Values of Assets Acquired and Liabilities Assumed (Details) $ in Thousands, $ in Millions					1 Months Ended	9 Months Ended
	May 07, 2021 USD ($)	Jan. 15, 2021 USD ($)	Aug. 04, 2020 USD ($)	May 27, 2020 USD ($)	Aug. 31, 2021 NZD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Assets acquired
Goodwill						$ 403,626		$ 187,411
Consideration paid
Cash paid, net of cash acquired						199,679	$ 54,757
Contingent consideration								$ 10,619
xMatters Holdings, Inc
Assets acquired
Accounts receivable	$ 6,716
Property and equipment	1,458
Goodwill	170,437
Other assets	5,433
Total assets acquired	279,574
Liabilities assumed
Accounts payable	1,164
Accrued expenses	5,517
Deferred revenue	34,421
Deferred tax liabilities	3,436
Other liabilities	5,056
Net assets acquired	229,980
Consideration paid
Cash paid	178,100
Cash paid, net of cash acquired						165,498
Fair value of common stock issued	64,482
Total						229,980
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	$ 78,940
Red Sky Technologies Inc.
Assets acquired
Accounts receivable		$ 2,926
Property and equipment		18
Goodwill		49,508
Other assets		242
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						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		$ 20,000
Techwan SA
Assets acquired
Accounts receivable				$ 921
Other current assets				235
Goodwill				12,678
Other assets				254
Total assets acquired				20,928
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						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 current assets			283
Property and equipment			118
Goodwill			22,629
Other assets			943
Total assets acquired			42,341
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		$ 2.5
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						$ 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