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Leases - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Topic 842 [Member] | SiriusDecisions, Inc [Member] | Facility Lease [Member]
Lessee Lease Description [Line Items]
Right-of-use asset impairments	$ 1.4

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of loss from impairment of right-of-use asset from operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 25
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121593497&loc=SL77918431-209957

+ Details

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- Details

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- Details

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- Details

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