Legal Proceedings	12 Months Ended
Dec. 31, 2014
Legal Proceedings [Abstract]
Legal Proceedings	Note 11 - Legal Proceedings The Company is or has been a party in a number of lawsuits or proceedings, including the following: Supervisory Goodwill Litigation – Tax Gross-up - The Company was a plaintiff in a legal proceeding, commenced in 1993, seeking recovery of damages from the United States Government for the loss of the Company's wholly-owned subsidiary, Carteret Savings Bank, F.A. (the "Supervisory Goodwill" legal proceedings). A Settlement Agreement in the Supervisory Goodwill legal proceedings between the Company, the Federal Deposit Insurance Corporation-Receiver ("FDIC-R") and the Department of Justice ("DOJ") on behalf of the United States of America (the "United States"), was executed (the "Settlement Agreement") which was subject to approval by the United States Court of Federal Claims (the "Court of Federal Claims"). On October 11, 2012, the Court of Federal Claims issued an order approving the Settlement Agreement, and on October 19, 2012, the United States paid $180,650,000 directly to AmBase (the "Settlement Amount"). As part of the Settlement Agreement, the Company is entitled to a tax gross-up in an amount to be determined if and when any federal taxes should be imposed on the Settlement Amount. Based on the Company's 2012 federal income tax return as filed (subject to IRS audit adjustment/review), in March 2013, the Company paid $500,729 of federal income taxes attributable to Alternative Minimum Tax ("AMT") rate calculations (the "2012 Federal Income Tax Paid"). Pursuant to the Settlement Agreement, Rule 60(b) of the Rules of the Court of Federal Claims will govern the process for receiving a tax gross-up. On May 3, 2013, the Company filed a Rule 60(b) Motion with the Court of Federal Claims seeking a tax gross-up from the United States for the 2012 federal income tax paid, plus applicable tax consequences relative to the reimbursement of this amount. The Company sought to: (i) reserve the right to seek a tax gross-up for any additional federal tax which could be owed as a result of additional taxes which may be imposed by the IRS upon tax return review or otherwise; and (ii) reserve the right to seek the economic value for deductions utilized against the Settlement Award. The DOJ, on behalf of the United States, filed their response brief in May 2013, and the Company filed its reply brief in June 2013. Subsequently, Senior Judge Smith held oral argument on June 12, 2013 and after the hearing filed an order directing the United States to pay AmBase reimbursement for 2012 Federal Income Taxes Paid as provided for in the Settlement Agreement, which amount was received by the Company in September 2013. On August 6, 2013, Senior Judge Smith issued an opinion which addressed the relief sought by AmBase. In summary, the Court held that the Settlement Agreement is a contract and that it entitles the Company to receive both "(1) the amount of the tax consequences resulting from taxation of the damages award plus (2) the tax consequences of receiving the first component." But the Court did not award additional damages for the second component of the damages at that time given the remaining uncertainty surrounding the ultimate tax treatment of the settlement proceeds and the gross-up, as well as uncertainty relating to the Company's future income. The Court indicated that either the Company or the government is entitled to seek further relief "if, and when, the facts justify." The Court also stated that the "plain meaning of the agreement precludes state taxes from being included in any possible future gross-up calculations." Additionally, the Court indicated that AmBase "would first have to generate income" before it could attempt to recover compensation for the use of its NOLs to shield the settlement proceeds from federal taxation. The Company believes that pursuant to the terms of the Settlement Agreement, the Company could seek to recover the value of its federal NOL carryforwards and/or Carteret Tax Basis previously utilized by the Company to reduce its 2012 federal taxable income in connection with the filing of the Company's 2012 federal income tax return. Any such recovery, however, would be dependent on numerous factors and circumstances, including but not limited to, whether or not the Company generated future federal taxable income, the timing and amount of future federal taxable income generated by the Company, if any, the expiration of current and previously utilized NOL carryforwards, the Court of Federal Claims interpretation of the Settlement Agreement and other legal and factual interpretations. As a result, the Company can give no assurances as to the realization, the amount or the timing of any such recovery, if any. For additional information, see Note 10 – to the Company's consolidated financial statements.

Note 11 - Legal Proceedings

The Company is or has been a party in a number of lawsuits or proceedings, including the following:

Supervisory Goodwill Litigation – Tax Gross-up - The Company was a plaintiff in a legal proceeding, commenced in 1993, seeking recovery of damages from the United States Government for the loss of the Company's wholly-owned subsidiary, Carteret Savings Bank, F.A. (the "Supervisory Goodwill" legal proceedings). A Settlement Agreement in the Supervisory Goodwill legal proceedings between the Company, the Federal Deposit Insurance Corporation-Receiver ("FDIC-R") and the Department of Justice ("DOJ") on behalf of the United States of America (the "United States"), was executed (the "Settlement Agreement") which was subject to approval by the United States Court of Federal Claims (the "Court of Federal Claims"). On October 11, 2012, the Court of Federal Claims issued an order approving the Settlement Agreement, and on October 19, 2012, the United States paid $180,650,000 directly to AmBase (the "Settlement Amount").

As part of the Settlement Agreement, the Company is entitled to a tax gross-up in an amount to be determined if and when any federal taxes should be imposed on the Settlement Amount. Based on the Company's 2012 federal income tax return as filed (subject to IRS audit adjustment/review), in March 2013, the Company paid $500,729 of federal income taxes attributable to Alternative Minimum Tax ("AMT") rate calculations (the "2012 Federal Income Tax Paid"). Pursuant to the Settlement Agreement, Rule 60(b) of the Rules of the Court of Federal Claims will govern the process for receiving a tax gross-up. On May 3, 2013, the Company filed a Rule 60(b) Motion with the Court of Federal Claims seeking a tax gross-up from the United States for the 2012 federal income tax paid, plus applicable tax consequences relative to the reimbursement of this amount. The Company sought to: (i) reserve the right to seek a tax gross-up for any additional federal tax which could be owed as a result of additional taxes which may be imposed by the IRS upon tax return review or otherwise; and (ii) reserve the right to seek the economic value for deductions utilized against the Settlement Award. The DOJ, on behalf of the United States, filed their response brief in May 2013, and the Company filed its reply brief in June 2013. Subsequently, Senior Judge Smith held oral argument on June 12, 2013 and after the hearing filed an order directing the United States to pay AmBase reimbursement for 2012 Federal Income Taxes Paid as provided for in the Settlement Agreement, which amount was received by the Company in September 2013.

On August 6, 2013, Senior Judge Smith issued an opinion which addressed the relief sought by AmBase. In summary, the Court held that the Settlement Agreement is a contract and that it entitles the Company to receive both "(1) the amount of the tax consequences resulting from taxation of the damages award plus (2) the tax consequences of receiving the first component." But the Court did not award additional damages for the second component of the damages at that time given the remaining uncertainty surrounding the ultimate tax treatment of the settlement proceeds and the gross-up, as well as uncertainty relating to the Company's future income. The Court indicated that either the Company or the government is entitled to seek further relief "if, and when, the facts justify." The Court also stated that the "plain meaning of the agreement precludes state taxes from being included in any possible future gross-up calculations." Additionally, the Court indicated that AmBase "would first have to generate income" before it could attempt to recover compensation for the use of its NOLs to shield the settlement proceeds from federal taxation.

The Company believes that pursuant to the terms of the Settlement Agreement, the Company could seek to recover the value of its federal NOL carryforwards and/or Carteret Tax Basis previously utilized by the Company to reduce its 2012 federal taxable income in connection with the filing of the Company's 2012 federal income tax return. Any such recovery, however, would be dependent on numerous factors and circumstances, including but not limited to, whether or not the Company generated future federal taxable income, the timing and amount of future federal taxable income generated by the Company, if any, the expiration of current and previously utilized NOL carryforwards, the Court of Federal Claims interpretation of the Settlement Agreement and other legal and factual interpretations. As a result, the Company can give no assurances as to the realization, the amount or the timing of any such recovery, if any. For additional information, see Note 10 – to the Company's consolidated financial statements.