v3.25.4

Note 8 - Financial Instruments - Other Investments, at Fair Value (Details) - USD ($) $ in Thousands | Dec. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Other Investments, Fair Value Disclosure | $ 57,258 | $ 35,262
CREO JV [Member] |  |
Other Investments, Fair Value Disclosure | 8,940 | 6,432
U.S. Insurance JV [Member] |  |
Other Investments, Fair Value Disclosure | 2,375 | 2,825
Equity Securities [Member] |  |
Other Investments, Fair Value Disclosure | 21,457 | 11,072
Placement Unit and Warrants [Member] |  |
Other Investments, Fair Value Disclosure | 19,997 | 1,587
Corporate Bond Securities [Member] |  |
Other Investments, Fair Value Disclosure | 535 | 531
Fair Value Receivables [Member] |  |
Notes receivable | 2,783 | 11,250
Interest In SPVs [Member] |  |
Other Investments, Fair Value Disclosure | 0 | 1,565
CK Capital Value Fund [Member] |  |
Other Investments, Fair Value Disclosure | $ 1,171 | $ 0

X
- Definition Amount of investments, other than trading securities, measured at fair value. + References No definition available. + Details
Name: | cohn_OtherInvestmentsFairValueDisclosure
Namespace Prefix: | cohn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of an agreement for an unconditional promise by the maker to pay the holder a definite sum of money at a future date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -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/2009/role/commonPracticeRef -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/2009/role/commonPracticeRef -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/2009/role/commonPracticeRef -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 + Details
Name: | us-gaap_NotesReceivableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=cohn_CREOJVMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=cohn_USInsuranceJVMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=cohn_PlacementUnitAndWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=cohn_FairValueReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=cohn_InterestInSpvsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=cohn_CkCapitalValueFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |