Organization	12 Months Ended
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization Siebert Financial Corp., a New York corporation incorporated in 1934, is a holding company that conducts its retail discount brokerage business through its wholly-owned subsidiary, Muriel Siebert & Co., Inc. (“MSCO”), a Delaware corporation and registered broker-dealer, its investment advisory business through its wholly-owned subsidiary, Siebert AdvisorNXT, Inc. (“AdvisorNXT”), a New York corporation registered with the SEC as a Registered Investment Advisor under the Investment Advisers Act of 1940, as amended, its insurance business through its wholly-owned subsidiary, Park Wilshire Companies, Inc. (“PWC”), a Texas corporation and licensed insurance agency, and KCA Technologies, LLC. (“KCAT”), a Nevada limited liability company and developer of robo-advisory technology. For purposes of this Form 10-K, the terms “Siebert,” “Company,” “we,” “us,” and “our” refer to Siebert Financial Corp., MSCO, AdvisorNXT, PWC, and KCAT collectively, unless the context otherwise requires. The Company is headquartered in New York, NY, with primary operations in New Jersey and California. The Company has offices throughout the U.S. and clients around the world. The Company’s SEC filings are available through the Company’s website at www.siebertnet.com, where investors are able to obtain copies of the Company’s public filings free of charge. The Company’s Common Stock, par value $.01 per share, trades on the Nasdaq Capital Market under the symbol “SIEB.” The Company primarily operates in the securities brokerage and asset management industry and has no other reportable segments. All of the Company's revenues for the years ended December 31, 2018 and 2017 were derived from its operations in the U.S. Transactions completed during 2018 Acquisition of KCAT On August 21, 2018, the Company acquired all of the issued and outstanding membership interests of KCAT from Kennedy Cabot Acquisition LLC, (“KCA”), one of the Company’s affiliates through common ownership, for approximately $690,000. This transaction was accounted for as an asset acquisition. KCAT is a technology company initially tasked with developing a sophisticated Robo-Advisor for AdvisorNXT, the Company’s RIA. The Robo-Advisor provides clients with an automated wealth management solution intended to maximize portfolio returns based on the client’s specific risk tolerance. Acquisition of PWC In March 2018, the Company acquired all of the issued and outstanding shares of PWC from three related parties for approximately $110,000 (equal to the amount of cash held in PWC’s bank accounts at the time). The Board of Directors reviewed the transaction and concluded that, given the amount of the purchase price, the fact that the purchase price equaled the cash on hand in PWC’s bank accounts, and that PWC had no liabilities, the acquisition was not material and did not require a third party valuation. The sellers agreed to indemnify the Company from all liability attendant to the prior business activities of PWC. David J. Gebbia agreed to continue as the unpaid CEO of PWC. Transactions completed in prior to 2018 Acquisition of StockCross Retail Assets The Company entered into an agreement to acquire most of the retail broker-dealer business of StockCross Financial Services (“StockCross”), an affiliate of the Company, in exchange for 5,072,062 shares of the Company’s restricted Common Stock, subject to a two-year lock-up, valued at $19,984,000. Approximately $125,000 of legal and appraisal fees were incurred in the consummation of the transaction. In addition, the Company acquired various rent obligations, transferred employees and customer lists. As StockCross was determined to be an entity under common control, the assets and liabilities transferred to the Company from StockCross were recorded at historical cost in accordance with ASC 805-50, Business Combinations - Related Issues. The difference between the consideration paid and historical cost of the net assets acquired was recorded as an equity distribution by the Company. ASC 805-50 transactions between entities under common control stipulates a common control transaction as a transfer of net assets or an exchange of equity interests between entities under common control. Since the assets acquired from StockCross had a book value of nil, the fair market value of assets acquired, approximately $19,984,000, was reflected as nil for financial statement purposes as of the date of transfer as required by ASC 805-50. Additionally, as the transfer of net assets and related operations did not change the composition of MSCO as a reporting entity, retrospective combination of the entities for all periods presented as if the combination has been in effect since the inception of common control is not required. Accordingly, the net assets transferred and related operations are presented prospectively as of the effective date of November 30, 2017.

1. Organization

Siebert Financial Corp., a New York corporation incorporated in 1934, is a holding company that conducts its retail discount brokerage business through its wholly-owned subsidiary, Muriel Siebert & Co., Inc. (“MSCO”), a Delaware corporation and registered broker-dealer, its investment advisory business through its wholly-owned subsidiary, Siebert AdvisorNXT, Inc. (“AdvisorNXT”), a New York corporation registered with the SEC as a Registered Investment Advisor under the Investment Advisers Act of 1940, as amended, its insurance business through its wholly-owned subsidiary, Park Wilshire Companies, Inc. (“PWC”), a Texas corporation and licensed insurance agency, and KCA Technologies, LLC. (“KCAT”), a Nevada limited liability company and developer of robo-advisory technology. For purposes of this Form 10-K, the terms “Siebert,” “Company,” “we,” “us,” and “our” refer to Siebert Financial Corp., MSCO, AdvisorNXT, PWC, and KCAT collectively, unless the context otherwise requires.

The Company is headquartered in New York, NY, with primary operations in New Jersey and California. The Company has offices throughout the U.S. and clients around the world. The Company’s SEC filings are available through the Company’s website at www.siebertnet.com, where investors are able to obtain copies of the Company’s public filings free of charge. The Company’s Common Stock, par value $.01 per share, trades on the Nasdaq Capital Market under the symbol “SIEB.”

The Company primarily operates in the securities brokerage and asset management industry and has no other reportable segments. All of the Company's revenues for the years ended December 31, 2018 and 2017 were derived from its operations in the U.S.

Transactions completed during 2018

Acquisition of KCAT

On August 21, 2018, the Company acquired all of the issued and outstanding membership interests of KCAT from Kennedy Cabot Acquisition LLC, (“KCA”), one of the Company’s affiliates through common ownership, for approximately $690,000. This transaction was accounted for as an asset acquisition. KCAT is a technology company initially tasked with developing a sophisticated Robo-Advisor for AdvisorNXT, the Company’s RIA. The Robo-Advisor provides clients with an automated wealth management solution intended to maximize portfolio returns based on the client’s specific risk tolerance.

Acquisition of PWC

In March 2018, the Company acquired all of the issued and outstanding shares of PWC from three related parties for approximately $110,000 (equal to the amount of cash held in PWC’s bank accounts at the time). The Board of Directors reviewed the transaction and concluded that, given the amount of the purchase price, the fact that the purchase price equaled the cash on hand in PWC’s bank accounts, and that PWC had no liabilities, the acquisition was not material and did not require a third party valuation.

The sellers agreed to indemnify the Company from all liability attendant to the prior business activities of PWC. David J. Gebbia agreed to continue as the unpaid CEO of PWC.

Transactions completed in prior to 2018

Acquisition of StockCross Retail Assets

The Company entered into an agreement to acquire most of the retail broker-dealer business of StockCross Financial Services (“StockCross”), an affiliate of the Company, in exchange for 5,072,062 shares of the Company’s restricted Common Stock, subject to a two-year lock-up, valued at $19,984,000. Approximately $125,000 of legal and appraisal fees were incurred in the consummation of the transaction. In addition, the Company acquired various rent obligations, transferred employees and customer lists.

As StockCross was determined to be an entity under common control, the assets and liabilities transferred to the Company from StockCross were recorded at historical cost in accordance with ASC 805-50, Business Combinations - Related Issues. The difference between the consideration paid and historical cost of the net assets acquired was recorded as an equity distribution by the Company. ASC 805-50 transactions between entities under common control stipulates a common control transaction as a transfer of net assets or an exchange of equity interests between entities under common control. Since the assets acquired from StockCross had a book value of nil, the fair market value of assets acquired, approximately $19,984,000, was reflected as nil for financial statement purposes as of the date of transfer as required by ASC 805-50.

Additionally, as the transfer of net assets and related operations did not change the composition of MSCO as a reporting entity, retrospective combination of the entities for all periods presented as if the combination has been in effect since the inception of common control is not required. Accordingly, the net assets transferred and related operations are presented prospectively as of the effective date of November 30, 2017.