v3.25.4

Note 8 - Financial Instruments - Financial Instruments Sold, Not Yet Purchased (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Trading securities sold, not yet purchased	$ 36,617	$ 36,432
Equity securities	0	1,651
Other investments sold, not yet purchased	0	1,651
Corporate Bonds and Redeemable Preferred Stock [Member]
Trading securities sold, not yet purchased	8,107	7,342
Equity Securities [Member]
Trading securities sold, not yet purchased	463	83
Equity securities	0	1,181
Other investments sold, not yet purchased	0	1,181
Derivative [Member]
Trading securities sold, not yet purchased	4,245	4,050
Equity Derivatives [Member]
Equity securities	0	470
Other investments sold, not yet purchased	0	470
US Government Agencies Debt Securities [Member]
Trading securities sold, not yet purchased	0	40
US Treasury Securities [Member]
Trading securities sold, not yet purchased	$ 23,802	$ 24,917

X

- Definition

Represents other investment sold not yet purchased.

+ References

No definition available.

+ Details

Name:	cohn_OtherInvestmentSoldNotYetPurchased
Namespace Prefix:	cohn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Fair value of obligations incurred from short sales.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-11

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-11

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-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

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E

Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 940
-SubTopic 320
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479035/940-320-45-2

+ Details

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

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_DerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=cohn_EquityDerivativesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: