Debt Instrument, Floor, Percentage

No definition available.

Name:	rily_DebtInstrumentFloorPercentage
Namespace Prefix:	rily_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Periodic Payment, Period

+ References

No definition available.

+ Details

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Namespace Prefix:	rily_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Dividends Paid, Equal To The Greater Of Gross Proceeds, Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	rily_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Dividends Paid, Equal To The Greater Of Net After-tax Proceeds, Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	rily_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing Receivable, Unrealized Gain (Loss)

+ References

No definition available.

+ Details

Name:	rily_FinancingReceivableUnrealizedGainLoss
Namespace Prefix:	rily_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line Of Credit Facility, Maximum Borrowing Capacity, Increase

+ References

No definition available.

+ Details

Name:	rily_LineOfCreditFacilityMaximumBorrowingCapacityIncrease
Namespace Prefix:	rily_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loans Receivable, Fair Value Disclosure, Drawn

+ References

No definition available.

+ Details

Name:	rily_LoansReceivableFairValueDisclosureDrawn
Namespace Prefix:	rily_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Take-private Transaction, Price

+ References

No definition available.

+ Details

Name:	rily_TakePrivateTransactionPrice
Namespace Prefix:	rily_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of nonaccrual to total financing receivable outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (2)
-Publisher SEC

+ Details

Name:	srt_FinancingReceivableNonaccrualToOutstandingPercent
Namespace Prefix:	srt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value portion of amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties.

+ References

+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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

- Definition

Amount of the required periodic payments applied to principal.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9

+ Details

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

- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Publisher FASB
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-Topic 835
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-Paragraph 1
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
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-Section 50
-Paragraph 1D
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

+ Details

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

- Definition

This item represents the estimated amount of gains or losses included in earnings during the period attributable to changes in instrument-specific credit risk arising from loans and other receivables held as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-30

+ Details

Name:	us-gaap_FairValueOptionCreditRiskGainsLossesOnAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
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-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
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-Topic 942
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-Topic 942
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-Topic 942
-SubTopic 210
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(e)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- Definition

Amortized cost of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
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-Paragraph 16
-Subparagraph (c)
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-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
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-Topic 942
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-Topic 942
-SubTopic 210
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-Topic 210
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-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
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-Topic 942
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-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13)(3)(a))
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-Topic 210
-SubTopic 10
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-Section S50
-Paragraph 8
-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
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-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

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-Topic 470
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-Section 50
-Paragraph 6
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-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 8
-Publisher FASB
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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

- Definition

Percentage added to reference rate used to compute variable rate on loan receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-3

+ Details

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

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-10

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-Topic 825
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-Section 55
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-Topic 825
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-Topic 825
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-Topic 825
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Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-28

+ Details

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

- Definition

Fair value portion of an agreement for an unconditional promise by the maker to pay the holder a definite sum of money at a future date.

+ References

+ Details

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

- Definition

The cash outflow for the purchase of amounts due from customers, clients, lessees, borrowers, or others under the terms of its agreements therewith.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

Name:	us-gaap_PaymentsToAcquireFinanceReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the collection of receivables arising from the financing of goods and services.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-12

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

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

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-Topic 230
-SubTopic 10
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-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

Name:	us-gaap_RepaymentsOfLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
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-Subparagraph (b)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(i)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

+ Details

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

- Definition

The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt.

+ References

+ Details

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

- 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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- Details

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LOANS RECEIVABLE, AT FAIR VALUE - Additional information (Details) - USD ($)						1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Oct. 01, 2026	Jan. 21, 2026	Jul. 29, 2025	Dec. 18, 2023	Aug. 21, 2023	Feb. 28, 2026	Sep. 30, 2026	Mar. 31, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025	May 14, 2026	Nov. 02, 2023	Feb. 27, 2023
Line of Credit Facility [Line Items]
Financing receivable, unrealized gain (loss)							$ 1,215,000		$ 1,299,000	$ 12,005,000	$ (5,997,000)
Financing receivable, nonaccrual							$ 0			$ 0		$ 1,835,000
Nonaccrual to outstanding, percent							0.00%			0.00%		7.00%
Financing receivable, 90 days or more past due, still accruing							$ 21,276,000			$ 21,276,000		$ 320,285,000
Fair value, option, credit risk, gains (losses) on assets							1,215,000		$ 1,316,000	3,223,000	$ (5,980,000)
Loans receivable							10,798,000			10,798,000		26,303,000
Loans receivable, at fair value							10,798,000			10,798,000		26,303,000
Amended Exela A R Facility
Line of Credit Facility [Line Items]
Facility increase													$ 4,625,000
Borrowing capacity credit facility													$ 24,625,000
Related Party
Line of Credit Facility [Line Items]
Loans receivable							1,086,000			1,086,000		2,835,000
Loans receivable, at fair value							1,086,000			1,086,000		2,835,000
Conn’s \| Related Party
Line of Credit Facility [Line Items]
Proceeds from collection of finance receivables										8,600,000
Torticity, LLC \| Related Party
Line of Credit Facility [Line Items]
Loans receivable														$ 15,369,000
Loans receivable, fair value disclosure, drawn														$ 6,690,000
Loans receivable, basis spread on variable rate														15.00%
Torticity, LLC \| Related Party \| Cash
Line of Credit Facility [Line Items]
Loans receivable, basis spread on variable rate														7.50%
Torticity, LLC \| Related Party \| Payment in Kind (PIK) Note
Line of Credit Facility [Line Items]
Loans receivable, basis spread on variable rate														7.50%
XBP Americas, LLC \| Related Party
Line of Credit Facility [Line Items]
Loans receivable							6,525,000			6,525,000		15,459,000
Accounts receivable, fair value							496,000			496,000		1,440,000
Notes receivable, fair value												4,516,000
Exela Loan \| Related Party
Line of Credit Facility [Line Items]
Loans receivable															$ 31,500,000
Loans receivable, basis spread on variable rate															7.50%
Repayments of lines of credit			$ 1,250,000
Debt instrument, periodic payment, period			60 days
Outstanding notes payable			$ 1,000,000
Repayments of long-term debt							3,000,000			9,250,000
Carrying amount							6,525,000			6,525,000		15,775,000
Exela Loan \| Related Party \| Subsequent Event
Line of Credit Facility [Line Items]
Repayments of lines of credit	$ 6,525,000
Exela AR Facility \| Related Party
Line of Credit Facility [Line Items]
Proceeds from collection of finance receivables							11,643,000			30,629,000
Notes receivable, fair value												5,000,000
Carrying amount							496,000			496,000		1,440,000
Debt instrument, unamortized discount												500,000
Repayments of unsecured debt		$ 5,000,000
Payments to acquire finance receivables		$ 22,623,000
Retail Industry \| Conn’s \| Related Party
Line of Credit Facility [Line Items]
Loans receivable, at fair value				$ 108,000,000
Debt instrument, floor, percentage				4.80%
Debt instrument, basis spread on variable rate				8.00%
Freedom VCM, Inc
Line of Credit Facility [Line Items]
Interest rate					12.00%
Dividends paid, equal to the greater of net after-tax proceeds, percentage					80.00%
Dividends paid, equal to the greater of gross proceeds, percentage					50.00%
Take-private transaction, price					$ 227,296,000
Proceeds from collection of finance receivables						$ 1,855,000		$ 1,855,000
Freedom VCM, Inc \| First Priority Security Interest
Line of Credit Facility [Line Items]
Loans receivable					$ 200,506,000
Conn’s, Inc. \| Related Party
Line of Credit Facility [Line Items]
Loans receivable												0
B.Riley Principal Investments, LLC ("BRPI")
Line of Credit Facility [Line Items]
Loans receivable							$ 0			0
Financing receivable, nonaccrual, interest income										$ 0		$ 0
B.Riley Principal Investments, LLC ("BRPI") \| Torticity, LLC \| Related Party
Line of Credit Facility [Line Items]
Loans receivable														$ 25,000,000
Loans receivable, fair value disclosure, drawn														$ 15,000,000