ACQUISITIONS (Details 2) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Weighted average basic shares outstanding (in shares)	21,216,829	17,935,254	20,311,231	17,212,716
Weighted average diluted shares outstanding (in shares)	22,119,055	17,935,254	20,984,757	17,547,073
United Online Inc [Member]
Revenues	$ 84,634	$ 64,377	$ 173,853	$ 126,105
Net loss attributable to B. Riley Financial, Inc.	$ (2,473)	$ (6,416)	$ 12,860	$ (15,634)
Basic (loss) earnings per share (in dollars per share)	$ (0.10)	$ (0.28)	$ 0.53	$ (0.62)
Diluted (loss) earnings per share (in dollars per shares)	$ (0.10)	$ (0.28)	$ 0.52	$ (0.62)
Weighted average basic shares outstanding (in shares)	24,256,020	22,766,887	24,135,371	25,142,864
Weighted average diluted shares outstanding (in shares)	24,256,020	22,766,887	24,808,897	25,142,864

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e1505-109256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e1448-109256

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