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.

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of estimated penalties accrued as of the balance sheet date arising from income tax examinations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319

+ Details

Name:	us-gaap_IncomeTaxExaminationPenaltiesAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Business Combination, Consideration Transferred, Deferred Consideration

+ References

No definition available.

+ Details

Name:	zi_BusinessCombinationConsiderationTransferredDeferredConsideration
Namespace Prefix:	zi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=zi_DiscoverOrgHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=zi_KomikoLTDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=zi_NeverBounceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=zi_PreAcquisitionZoomInformationIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitment and Contingencies (Details) - USD ($) $ in Millions	Feb. 01, 2021	Feb. 01, 2020	Jun. 30, 2020	Dec. 31, 2019	Oct. 09, 2019	Dec. 31, 2018	Sep. 30, 2018
Business Acquisition [Line Items]
Liability for taxes owed and related penalties and interest			$ 2.1	$ 2.1
DiscoverOrg Holdings
Business Acquisition [Line Items]
Liability for taxes owed and related penalties and interest				2.1		$ 1.4
Deferred consideration	$ 10.0	$ 25.0
Komiko
Business Acquisition [Line Items]
Potential earnout payment					$ 4.0
Komiko \| DiscoverOrg Holdings
Business Acquisition [Line Items]
Potential earnout payment				4.0
NeverBounce
Business Acquisition [Line Items]
Potential earnout payment			$ 1.6
NeverBounce \| DiscoverOrg Holdings
Business Acquisition [Line Items]
Potential earnout payment				$ 1.6			$ 2.0
Pre-Acquisition ZI \| Forecast
Business Acquisition [Line Items]
Deferred consideration	$ 10.0