XML 89 R68.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Stock-Based Compensation Plans - Summary of RSU Activity (Parenthetical) (Details) | 12 Months Ended
--- | ---
Dec. 31, 2018 shares
RSUs |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
RSUs vested but not yet delivered | 59,000

X
- Definition Share based compensation arrangement by share based payment award equity instruments other than options vested but not yet delivered. + References No definition available. + Details
Name: | cars_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedButNotYetDelivered
Namespace Prefix: | cars_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |