XML 51 R37.htm IDEA: XBRL DOCUMENT
v3.21.1

Description of Business | 3 Months Ended | 9 Months Ended
--- | --- | ---
Mar. 31, 2021 loan program | Sep. 30, 2020 USD ($)
Description Of Business [Abstract] |  |
Number of business programs | program | 2 |
Additional number of Consumer Loans required to group advances | loan | 50 |
Servicing fee percentage in collections | 20.00% |
One-time enrollment fee in program | $ |  | $ 9,850
Payment Holdback Percentage |  | 50.00%

X
- Definition Additional Number Of Consumer Loans Required To Group Advances + References No definition available. + Details
Name: | cacc_AdditionalNumberOfConsumerLoansRequiredToGroupAdvances
Namespace Prefix: | cacc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description Of Business [Abstract] + References No definition available. + Details
Name: | cacc_DescriptionOfBusinessAbstract
Namespace Prefix: | cacc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Business Programs + References No definition available. + Details
Name: | cacc_NumberOfBusinessPrograms
Namespace Prefix: | cacc_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Payment Holdback Percentage + References No definition available. + Details
Name: | cacc_PaymentHoldbackPercentage
Namespace Prefix: | cacc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenue From Enrollment And Registration Fees In Program + References No definition available. + Details
Name: | cacc_RevenueFromEnrollmentAndRegistrationFeesInProgram
Namespace Prefix: | cacc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Service fee income as a percentage of collections. + References No definition available. + Details
Name: | cacc_ServiceFeeIncomeAsPercentageOfCollections
Namespace Prefix: | cacc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration