Organization	6 Months Ended
Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization and basis of presentation Organization Oppenheimer Holdings Inc. ("OPY" or the "Parent") is incorporated under the laws of the State of Delaware. The condensed consolidated financial statements include the accounts of OPY and its consolidated subsidiaries (together, the "Company"). The Company engages in a broad range of activities in the financial services industry, including retail securities brokerage, institutional sales and trading, market-making, research, investment banking (both corporate and public finance), investment advisory and asset management services and trust services. The Company has 91 retail branch offices in the United States and has institutional businesses located in London, Tel Aviv, and Hong Kong. The principal subsidiaries of OPY are Oppenheimer & Co. Inc. ("Oppenheimer"), a registered broker-dealer in securities and investment adviser under the Investment Advisers Act of 1940; Oppenheimer Asset Management Inc. ("OAM") and its wholly-owned subsidiary, Oppenheimer Investment Management LLC, both registered investment advisers under the Investment Advisers Act of 1940; Oppenheimer Trust Company of Delaware ("Oppenheimer Trust"), a limited purpose trust company that provides fiduciary services such as trust and estate administration and investment management; OPY Credit Corp., which offers syndication as well as trading of issued corporate loans; Oppenheimer Europe Ltd., based in the United Kingdom, with offices in the Isle of Jersey and Switzerland, which provides institutional equities and fixed income brokerage and corporate finance and is regulated by the Financial Conduct Authority; Oppenheimer Investments Asia Limited, based in Hong Kong, China, which provides fixed income and equities brokerage services to institutional investors and is regulated by the Securities and Futures Commission; and Oppenheimer Multifamily Housing & Healthcare Finance, Inc. ("OMHHF") which was formerly engaged in Federal Housing Administration ("FHA")-insured commercial mortgage origination and servicing. During 2016, the Company sold substantially all of the assets of OMHHF and ceased its operations. Oppenheimer owns Freedom Investments, Inc. ("Freedom"), a registered broker dealer in securities, which provides discount brokerage services, and Oppenheimer Israel (OPCO) Ltd., which is engaged in offering investment services in the State of Israel. Oppenheimer holds a trading permit on the New York Stock Exchange and is a member of several other regional exchanges in the United States. Basis of Presentation The accompanying condensed consolidated financial statements of the Company have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the "SEC") regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America ("U.S. GAAP") for complete financial statements and should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 (the "Form 10-K"). The accompanying December 31, 2017 condensed consolidated balance sheet data was derived from the audited consolidated financial statements, but does not include all disclosures required by U.S. GAAP for annual financial statement purposes. The accompanying condensed consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods presented. Preparing financial statements requires management to make estimates and assumptions that affect the amounts that are reported in the financial statements and the accompanying disclosures. Although these estimates are based on management's knowledge of current events and actions that the Company may undertake in the future, actual results may differ materially from the estimates. The condensed consolidated results of operations for the six month period ended June 30, 2018 are not necessarily indicative of the results to be expected for any future interim or annual period. Certain prior period amounts have been reclassified to conform to the current period presentation. Accounting standards require the Company to present non-controlling interests as a separate component of stockholders' equity on the Company's condensed consolidated balance sheet. As of June 30, 2018, the Company owned 83.68% of OMHHF and the non-controlling interest recorded on the condensed consolidated balance sheet was $349,000.

Organization and basis of presentation

Organization

Oppenheimer Holdings Inc. ("OPY" or the "Parent") is incorporated under the laws of the State of Delaware. The condensed consolidated financial statements include the accounts of OPY and its consolidated subsidiaries (together, the "Company"). The Company engages in a broad range of activities in the financial services industry, including retail securities brokerage, institutional sales and trading, market-making, research, investment banking (both corporate and public finance), investment advisory and asset management services and trust services.

The Company has 91 retail branch offices in the United States and has institutional businesses located in London, Tel Aviv, and Hong Kong. The principal subsidiaries of OPY are Oppenheimer & Co. Inc. ("Oppenheimer"), a registered broker-dealer in securities and investment adviser under the Investment Advisers Act of 1940; Oppenheimer Asset Management Inc. ("OAM") and its wholly-owned subsidiary, Oppenheimer Investment Management LLC, both registered investment advisers under the Investment Advisers Act of 1940; Oppenheimer Trust Company of Delaware ("Oppenheimer Trust"), a limited purpose trust company that provides fiduciary services such as trust and estate administration and investment management; OPY Credit Corp., which offers syndication as well as trading of issued corporate loans; Oppenheimer Europe Ltd., based in the United Kingdom, with offices in the Isle of Jersey and Switzerland, which provides institutional equities and fixed income brokerage and corporate finance and is regulated by the Financial Conduct Authority; Oppenheimer Investments Asia Limited, based in Hong Kong, China, which provides fixed income and equities brokerage services to institutional investors and is regulated by the Securities and Futures Commission; and Oppenheimer Multifamily Housing & Healthcare Finance, Inc. ("OMHHF") which was formerly engaged in Federal Housing Administration ("FHA")-insured commercial mortgage origination and servicing. During 2016, the Company sold substantially all of the assets of OMHHF and ceased its operations.

Oppenheimer owns Freedom Investments, Inc. ("Freedom"), a registered broker dealer in securities, which provides discount brokerage services, and Oppenheimer Israel (OPCO) Ltd., which is engaged in offering investment services in the State of Israel. Oppenheimer holds a trading permit on the New York Stock Exchange and is a member of several other regional exchanges in the United States.

Basis of Presentation

The accompanying condensed consolidated financial statements of the Company have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the "SEC") regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America ("U.S. GAAP") for complete financial statements and should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 (the "Form 10-K"). The accompanying December 31, 2017 condensed consolidated balance sheet data was derived from the audited consolidated financial statements, but does not include all disclosures required by U.S. GAAP for annual financial statement purposes. The accompanying condensed consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods presented. Preparing financial statements requires management to make estimates and assumptions that affect the amounts that are reported in the financial statements and the accompanying disclosures. Although these estimates are based on management's knowledge of current events and actions that the Company may undertake in the future, actual results may differ materially from the estimates. The condensed consolidated results of operations for the six month period ended June 30, 2018 are not necessarily indicative of the results to be expected for any future interim or annual period.

Certain prior period amounts have been reclassified to conform to the current period presentation.

Accounting standards require the Company to present non-controlling interests as a separate component of stockholders' equity on the Company's condensed consolidated balance sheet. As of June 30, 2018, the Company owned 83.68% of OMHHF and the non-controlling interest recorded on the condensed consolidated balance sheet was $349,000.