Commitments and contingencies.

No definition available.

Name:	carg_CommitmentsAndContingenciesLineItems
Namespace Prefix:	carg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Guarantee income.

+ References

No definition available.

+ Details

Name:	carg_GuaranteeIncome
Namespace Prefix:	carg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Loss contingent liabilities.

+ References

No definition available.

+ Details

Name:	carg_LossContingentLiabilities
Namespace Prefix:	carg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of days guarantee period.

+ References

No definition available.

+ Details

Name:	carg_NumberOfDaysGuaranteePeriod
Namespace Prefix:	carg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=124440162&loc=d3e12069-110248

+ Details

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

- Definition

Describe the approximate term of the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=124440162&loc=d3e12069-110248

+ Details

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

- Definition

Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=126999549&loc=SL98516268-108586

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(1)(a))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(2))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

Name:	us-gaap_RestrictedCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

Commitments and Contingencies - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) Days	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2021	Jan. 14, 2021
Commitments And Contingencies [Line Items]
Restricted cash	$ 22,918		$ 22,918		$ 16,336
Guarantee income	$ 2,292	$ 1,628	$ 5,595	$ 2,275
Car Offer
Commitments And Contingencies [Line Items]
Business acquisition, percentage of interest acquired	51.00%		51.00%			51.00%	51.00%
Guarantees, description			CarOffer provides certain guarantees to dealers through its 45-Day Guaranteed Bid and OfferGuard product offerings, which are accounted for under ASC Topic 460, Guarantees.
Number of days guarantee period \| Days			45
Guarantees	$ 100,746		$ 100,746		76,075
Loss contingent liabilities	$ 0		$ 0		$ 0