Segment And Geographic Information (Schedule Of Segment Reporting Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Principal transactions and other income	$ (2,406)	$ 414
Total revenues	17,770	11,140
Salaries/Wages	14,134	6,364
Other Operating Expense	5,198	4,844
Impairment of goodwill	7,883
Total operating expenses	27,215	11,208
Operating income (loss)	(9,445)	(68)
Interest (income) expense	2,605	1,854
Income (loss) from equity method affiliates	(107)	(8)
Income (loss) before income tax expense (benefit)	(12,157)	(1,930)
Income tax expense (benefit)	(372)	(106)
Net income (loss)	(11,785)	(1,824)
Less: Net income (loss) attributable to the non-controlling interest	(8,683)	(622)
Net income (loss) attributable to Cohen & Company Inc.	(3,102)	(1,202)
Depreciation and amortization (included in total operating expense)	80	81
Operating Segments [Member]
Segment Reporting Information [Line Items]
Principal transactions and other income	(2,406)	414
Total revenues	17,770	11,140
Salaries/Wages	13,027	5,669
Other Operating Expense	3,804	3,704
Impairment of goodwill	7,883
Total operating expenses	24,714	9,373
Operating income (loss)	(6,944)	1,767
Interest (income) expense	75	55
Income (loss) from equity method affiliates	(107)	(8)
Income (loss) before income tax expense (benefit)	(7,126)	1,704
Net income (loss)	(7,126)	1,704
Net income (loss) attributable to Cohen & Company Inc.	(7,126)	1,704
Depreciation and amortization (included in total operating expense)	5	6
Unallocated [Member]
Segment Reporting Information [Line Items]
Salaries/Wages	1,107	695
Other Operating Expense	1,394	1,140
Total operating expenses	2,501	1,835
Operating income (loss)	(2,501)	(1,835)
Interest (income) expense	2,530	1,799
Income (loss) before income tax expense (benefit)	(5,031)	(3,634)
Income tax expense (benefit)	(372)	(106)
Net income (loss)	(4,659)	(3,528)
Less: Net income (loss) attributable to the non-controlling interest	(8,683)	(622)
Net income (loss) attributable to Cohen & Company Inc.	4,024	(2,906)
Depreciation and amortization (included in total operating expense)	75	75
Capital Markets [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Principal transactions and other income	9	1
Total revenues	18,570	8,725
Salaries/Wages	11,910	4,547
Other Operating Expense	3,277	2,911
Impairment of goodwill	7,883
Total operating expenses	23,070	7,458
Operating income (loss)	(4,500)	1,267
Interest (income) expense	75	55
Income (loss) before income tax expense (benefit)	(4,575)	1,212
Net income (loss)	(4,575)	1,212
Net income (loss) attributable to Cohen & Company Inc.	(4,575)	1,212
Depreciation and amortization (included in total operating expense)	4	5
Asset Management [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Principal transactions and other income	116	97
Total revenues	1,731	2,099
Salaries/Wages	1,117	1,122
Other Operating Expense	477	693
Total operating expenses	1,594	1,815
Operating income (loss)	137	284
Income (loss) from equity method affiliates	200
Income (loss) before income tax expense (benefit)	337	284
Net income (loss)	337	284
Net income (loss) attributable to Cohen & Company Inc.	337	284
Depreciation and amortization (included in total operating expense)	1	1
Principal Investing [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Principal transactions and other income	(2,531)	316
Total revenues	(2,531)	316
Other Operating Expense	50	100
Total operating expenses	50	100
Operating income (loss)	(2,581)	216
Income (loss) from equity method affiliates	(307)	(8)
Income (loss) before income tax expense (benefit)	(2,888)	208
Net income (loss)	(2,888)	208
Net income (loss) attributable to Cohen & Company Inc.	(2,888)	208
Net Trading [Member]
Segment Reporting Information [Line Items]
Total revenue	18,561	8,724
Net Trading [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	18,561	8,724
Net Trading [Member] | Capital Markets [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	18,561	8,724
Asset Management [Member]
Segment Reporting Information [Line Items]
Total revenue	1,615	2,002
Asset Management [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	1,615	2,002
Asset Management [Member] | Asset Management [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 1,615	$ 2,002