Organization and Liquidity	12 Months Ended
Dec. 31, 2019
Organization and Liquidity [Abstract]
Organization and Liquidity	Note 1 – Organization and Liquidity AmBase Corporation (the “Company” or “AmBase”) is a Delaware corporation that was incorporated in 1975. AmBase is a holding company. At December 31, 2019, the Company’s assets consisted primarily of cash and cash equivalents and tax assets. The Company is engaged in the management of its assets and liabilities. In June 2013, the Company purchased an equity interest in a real estate development property through a joint venture agreement to purchase and develop real property located at 105 through 111 West 57^th Street in New York, New York (the “111 West 57^th Property”). The Company is engaged in material disputes and litigation with the sponsors of the joint venture (the “Sponsor”), both mezzanine lenders to the joint venture (“Apollo” and “Spruce”), and the title owner of the 111 West 57^th Property, 111 West 57th Property Owner LLC (“Property Owner”). Despite ongoing litigation challenging the legitimacy of the actions taken in connection with the “Strict Foreclosure”, (as defined and as further discussed herein) in accordance with GAAP, the Company recorded an impairment for the full amount of its equity investment in the 111 West 57th Property in 2017. Prior to the Strict Foreclosure, the carrying value of the Company’s equity investment in the 111 West 57^th Property represented a substantial portion of the Company’s assets and net equity value. For additional information regarding the Company’s recording of an impairment of its equity investment in the 111 West 57^th Property in 2017 and the Company’s legal proceedings relating to the 111 West 57^th Property, including the Company’s challenge to the Strict Foreclosure, see Note 4 and Note 9. While the Company’s management is evaluating future courses of action to protect and/or recover the value of the Company’s equity investment in the 111 West 57^th Property, the adverse developments make it uncertain as to whether any such courses of action will be successful. Any such efforts are likely to require sustained effort over a period of time and substantial additional financial resources. Inability to recover all or most of such value would in all likelihood have a material adverse effect on the Company’s financial condition and future prospects. The Company can give no assurances with regard if it will prevail with respect to any of its claims. The Company has incurred operating losses and used cash for operating activities for the past several years. The Company has continued to keep operating expenses at a reduced level; however, there can be no assurance that the Company’s current level of operating expenses will not increase or that other uses of cash will not be necessary. The Company believes that based on its current level of operating expenses its existing cash and cash equivalents, together with the federal tax refund received in March 2020, will be sufficient to fund operating activities for at least the next twelve months from the financial statement issuance date. The Company's management expects that operating cash needs in 2020 will be met principally by the Company's current financial resources, which include the federal tax refund received in March 2020. Over the next several months, the Company will seek to manage its current level of cash and cash equivalents, including but not limited to reducing operating expenses and seeking recoveries from various sources, although this cannot be assured.

Note 1 – Organization and Liquidity

AmBase Corporation (the “Company” or “AmBase”) is a Delaware corporation that was incorporated in 1975. AmBase is a holding company. At December 31, 2019, the Company’s assets consisted primarily of cash and cash equivalents and tax assets. The Company is engaged in the management of its assets and liabilities.

In June 2013, the Company purchased an equity interest in a real estate development property through a joint venture agreement to purchase and develop real property located at 105 through 111 West 57^th Street in New York, New York (the “111 West 57^th Property”). The Company is engaged in material disputes and litigation with the sponsors of the joint venture (the “Sponsor”), both mezzanine lenders to the joint venture (“Apollo” and “Spruce”), and the title owner of the 111 West 57^th Property, 111 West 57th Property Owner LLC (“Property Owner”). Despite ongoing litigation challenging the legitimacy of the actions taken in connection with the “Strict Foreclosure”, (as defined and as further discussed herein) in accordance with GAAP, the Company recorded an impairment for the full amount of its equity investment in the 111 West 57th Property in 2017. Prior to the Strict Foreclosure, the carrying value of the Company’s equity investment in the 111 West 57^th Property represented a substantial portion of the Company’s assets and net equity value.

For additional information regarding the Company’s recording of an impairment of its equity investment in the 111 West 57^th Property in 2017 and the Company’s legal proceedings relating to the 111 West 57^th Property, including the Company’s challenge to the Strict Foreclosure, see Note 4 and Note 9.

While the Company’s management is evaluating future courses of action to protect and/or recover the value of the Company’s equity investment in the 111 West 57^th Property, the adverse developments make it uncertain as to whether any such courses of action will be successful. Any such efforts are likely to require sustained effort over a period of time and substantial additional financial resources. Inability to recover all or most of such value would in all likelihood have a material adverse effect on the Company’s financial condition and future prospects. The Company can give no assurances with regard if it will prevail with respect to any of its claims.

The Company has incurred operating losses and used cash for operating activities for the past several years. The Company has continued to keep operating expenses at a reduced level; however, there can be no assurance that the Company’s current level of operating expenses will not increase or that other uses of cash will not be necessary. The Company believes that based on its current level of operating expenses its existing cash and cash equivalents, together with the federal tax refund received in March 2020, will be sufficient to fund operating activities for at least the next twelve months from the financial statement issuance date. The Company's management expects that operating cash needs in 2020 will be met principally by the Company's current financial resources, which include the federal tax refund received in March 2020. Over the next several months, the Company will seek to manage its current level of cash and cash equivalents, including but not limited to reducing operating expenses and seeking recoveries from various sources, although this cannot be assured.