v3.20.2

Goodwill and Acquired Intangible Assets - Changes to Goodwill (Details) - USD ($) $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Jun. 30, 2020 | Oct. 09, 2019
Goodwill [Roll Forward] |  |  |  |
Ending balance | $ 966.8 |  |  |
Acquired Indefinite-lived Intangible Assets [Line Items] |  |  |  |
Goodwill | 966.8 |  | $ 966.8 |
DiscoverOrg Holdings |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Beginning balance | 445.7 | $ 439.7 |  |
Ending balance | 966.8 | 445.7 |  |
Acquired Indefinite-lived Intangible Assets [Line Items] |  |  |  |
Goodwill | 445.7 | 445.7 |  |
NeverBounce | DiscoverOrg Holdings |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Acquisition |  | 6.0 |  |
Ending balance | 6.0 |  |  |
Acquired Indefinite-lived Intangible Assets [Line Items] |  |  |  |
Goodwill | 6.0 |  |  |
Acquisition |  | $ 6.0 |  |
ZoomInfo HoldCo | DiscoverOrg Holdings |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Acquisition | 514.8 |  |  |
Acquired Indefinite-lived Intangible Assets [Line Items] |  |  |  |
Acquisition | 514.8 |  |  |
Komiko |  |  |  |
Acquired Indefinite-lived Intangible Assets [Line Items] |  |  |  |
Goodwill |  |  |  | $ 6.3
Komiko | DiscoverOrg Holdings |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Acquisition | 6.3 |  |  |
Acquired Indefinite-lived Intangible Assets [Line Items] |  |  |  |
Goodwill |  |  |  | $ 6.3
Acquisition | $ 6.3 |  |  |

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

X
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)(1)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=120320667&loc=SL49117168-202975 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillAcquiredDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_GoodwillRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=zi_DiscoverOrgHoldingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=zi_ZoomInfoHoldCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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