Debt instrument issuance date one.

No definition available.

Name:	rm_DebtInstrumentIssuanceDateOne
Namespace Prefix:	rm_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

The maturity date of the amortizing loan credit agreement, in CCYY-MM format.

+ References

No definition available.

+ Details

Name:	rm_DebtInstrumentMaturityMonthAndYear
Namespace Prefix:	rm_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt instrument revolving period end month and year.

+ References

No definition available.

+ Details

Name:	rm_DebtInstrumentRevolvingPeriodEndMonthAndYear
Namespace Prefix:	rm_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Topic 835
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+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ References

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+ Details

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

- 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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

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

- Definition

Amount of cash and cash equivalent restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposit with financial institution, and account with general characteristic of demand deposit. Cash equivalent includes, but is not limited to, short-term, highly liquid investment that is both readily convertible to known amount of cash and so near maturity that it presents insignificant risk of change in value because of change in interest rate.

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+ Details

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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- Details

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- Details

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- Details

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Debt - Summary of Company's Securitizations (Details) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2025	Mar. 31, 2025	Nov. 30, 2024	Jun. 30, 2024	Feb. 28, 2022	Oct. 31, 2021	Jul. 31, 2021	Jun. 30, 2026	Dec. 31, 2025	Jun. 30, 2025
Line of Credit Facility [Line Items]
Debt Balance								$ 1,675,942	$ 1,650,764
Restricted Cash Reserves								111,776	$ 94,174	$ 117,658
RMIT 2021-2
Line of Credit Facility [Line Items]
Issue Date							2021-07
Issue Amount							$ 200,000
Debt Balance								200,192
Restricted Cash Reserves								$ 2,083
Effective interest rate								2.30%
Revolving Period End Date								2026-07
Maturity Date								2033-08
RMIT 2021-3
Line of Credit Facility [Line Items]
Issue Date						2021-10
Issue Amount						$ 125,000
Debt Balance								$ 125,202
Restricted Cash Reserves								$ 1,471
Effective interest rate								3.90%
Revolving Period End Date								2026-09
Maturity Date								2033-10
RMIT 2022-1
Line of Credit Facility [Line Items]
Issue Date					2022-02
Issue Amount					$ 250,000
Debt Balance								$ 53,038
Restricted Cash Reserves								$ 2,646
Effective interest rate								5.20%
Revolving Period End Date								2025-02
Maturity Date								2032-03
RMIT 2024-1
Line of Credit Facility [Line Items]
Issue Date				2024-06
Issue Amount				$ 187,305
Debt Balance								$ 187,788
Restricted Cash Reserves								$ 1,078
Effective interest rate								6.20%
Revolving Period End Date								2027-05
Maturity Date								2036-07
RMIT 2024-2
Line of Credit Facility [Line Items]
Issue Date			2024-11
Issue Amount			$ 250,000
Debt Balance								$ 250,557
Restricted Cash Reserves								$ 1,418
Effective interest rate								5.30%
Revolving Period End Date								2026-11
Maturity Date								2033-12
RMIT 2025-1
Line of Credit Facility [Line Items]
Issue Date		2025-03
Issue Amount		$ 265,000
Debt Balance								$ 265,585
Restricted Cash Reserves								$ 1,489
Effective interest rate								5.30%
Revolving Period End Date								2027-03
Maturity Date								2034-04
RMIT 2025-2
Line of Credit Facility [Line Items]
Issue Date	2025-10
Issue Amount	$ 252,810
Debt Balance								$ 253,318
Restricted Cash Reserves								$ 1,389
Effective interest rate								4.80%
Revolving Period End Date								2027-10
Maturity Date								2037-11
Securitizations
Line of Credit Facility [Line Items]
Issue Amount								$ 1,530,115
Debt Balance								1,335,680
Restricted Cash Reserves								$ 11,574