XML 52 R42.htm IDEA: XBRL DOCUMENT
v3.19.1

Disclosure About Fair Value of Financial Instruments - Additional Information (Detail) | 3 Months Ended
--- | ---
Mar. 31, 2019
Fair Value Disclosures [Abstract] |
Turnover rate of loan portfolio | 1.2

X
- Definition The annual turnover of the finance receivables in the portfolio. + References No definition available. + Details
Name: | rm_FinanceReceivablePortfolioTurnoverRate
Namespace Prefix: | rm_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration