BUSINESS SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues - Services and fees	$ 21,150	$ 20,669	$ 82,176	$ 48,001
Revenues - Sale of goods	122	5	10,588	9,273
Total revenues	21,272	20,674	92,764	57,274
Direct cost of services	$ (5,213)	(5,135)	(20,530)	(17,001)
Cost of goods sold		(1,747)	(3,071)	(10,811)
Selling, general, and administrative expenses	$ (12,782)	(12,497)	$ (45,755)	(30,481)
Restructuring charge		2,548		2,548
Segment income (loss)	$ 3,277	(1,253)	$ 23,408	(3,567)
Consolidated operating income from reportable segments	5,275	2,030	31,135	5,976
Corporate and other expenses (includes restucturing charge of $1,006 in each of the three and nine month periods ended September 30, 2014)	(1,998)	(3,283)	(7,727)	(9,543)
Interest income	5	3	10	9
Interest expense	(64)	(53)	(735)	(1,130)
Income (loss) before income taxes	3,218	(1,303)	22,683	(4,688)
(Provision) benefit for income taxes	(600)	387	(8,060)	1,795
Net income (loss)	2,618	(916)	14,623	(2,893)
Net income attributable to noncontrolling interests	1,155	(48)	1,814	86
Net income (loss) attributable to B. Riley Financial, Inc.	1,463	(868)	12,809	(2,979)
Capital expenditures	25	101	196	143
Total assets	142,369		142,369		$ 138,990
Auction and Liquidation Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenues - Services and fees	5,727	3,397	28,861	14,627
Revenues - Sale of goods	122	5	10,588	9,273
Total revenues	5,849	3,402	39,449	23,900
Direct cost of services	$ (1,722)	(1,670)	(10,642)	(6,708)
Cost of goods sold		(1,747)	(3,071)	(10,811)
Selling, general, and administrative expenses	$ (1,260)	(1,460)	$ (7,725)	(7,292)
Restructuring charge		(1,339)		(1,339)
Depreciation and amortization	$ (45)	(19)	$ (147)	(92)
Segment income (loss)	$ 2,822	(2,833)	$ 17,864	(2,342)
Capital expenditures		2		38
Total assets	$ 25,415		$ 25,415		41,360
Valuation and Appraisal Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenues - Services and fees	7,945	7,764	22,972	23,499
Direct cost of services	(3,491)	(3,465)	(9,888)	(10,293)
Selling, general, and administrative expenses	$ (2,000)	(2,091)	$ (6,434)	(7,304)
Restructuring charge		(203)		(203)
Depreciation and amortization	$ (35)	(40)	$ (104)	(116)
Segment income (loss)	2,419	$ 1,965	6,546	5,583
Capital expenditures	7		24	1
Total assets	10,575		10,575		9,527
Capital markets reportable segment [Member]
Segment Reporting Information [Line Items]
Revenues - Services and fees	7,478	$ 9,508	30,343	9,875
Selling, general, and administrative expenses	(7,310)	(6,527)	(23,234)	(7,046)
Depreciation and amortization	(134)	(83)	(384)	(94)
Segment income (loss)	$ 34	2,898	6,725	2,735
Capital expenditures		$ 99	108	$ 104
Total assets	$ 64,069		64,069		48,878
Corporate and other [Member]
Segment Reporting Information [Line Items]
Capital expenditures	18		64
Total assets	$ 42,310		$ 42,310		$ 39,225