NET CAPITAL REQUIREMENTS - Schedule of broker-dealer, net capital requirement, SEC regulation (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
B. Riley Securities (“BRS”)
Broker-Dealer, Net Capital Requirement [Line Items]
Net capital	$ 123,458	$ 79,560
Excess capital	116,822	74,393
Net capital requirement	6,636	5,167
B. Riley Wealth Management (“BRWM”)
Broker-Dealer, Net Capital Requirement [Line Items]
Net capital	8,294	7,521
Excess capital	6,969	6,186
Net capital requirement	$ 1,325	$ 1,335

Broker Dealer, Net Capital Requirement [Line Items]

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Amount of net capital in excess of minimum required net capital, calculated under Alternative Standard.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Rule 15c3-1
-Number 240
-Section 15c3-1
-Publisher SEC

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Minimum amount of net capital of broker-dealer and its subsidiary, calculated under Alternative Standard.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Rule 15c3-1
-Number 240
-Section 15c3-1
-Publisher SEC

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Amount of net capital of broker-dealer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Rule 15c3-1
-Number 240
-Section 15c3-1
-Publisher SEC

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