Commitments, Contingencies And Guarantees	9 Months Ended
Sep. 30, 2018
Commitments, Contingencies And Guarantees [Abstract]
Commitments, Contingencies And Guarantees	12. Commitments, Contingencies and Guarantees Litigation The Company is subject to certain pending and threatened legal actions that arise out of the normal course of business. Litigation is inherently unpredictable, particularly in proceedings where claimants seek substantial or indeterminate damages, or which are in their early stages. The Company has not been able to quantify the actual loss or range of loss related to such legal proceedings, the manner in which they will be resolved, the timing of final resolution or the ultimate settlement. Management believes that the resolution of these actions will not have a material effect, if any, on the Company’s business or financial condition, but may have a material impact on the results of operations for a given period. The Company accounts for potential losses related to litigation in accordance with FASB ASC Topic 450, “Contingencies.” As of September 30, 2018 and 2017, reserves provided for potential losses related to litigation matters were not material. Trading Technologies Matter On February 3, 2010, Trading Technologies International, Inc. (“Trading Technologies”) filed a complaint in the U.S. District Court for the Northern District of Illinois, Eastern Division, against IBG, Inc., IBG LLC, Holdings, and IB LLC. Thereafter, Trading Technologies dismissed IBG, Inc. and Holdings from the case, leaving only IBG LLC and IB LLC as defendants (“Defendants”). The operative complaint, as amended, alleges that the Defendants have infringed and continue to infringe twelve U.S. patents held by Trading Technologies. Trading Technologies is seeking, among other things, unspecified damages and injunctive relief (“the Litigation”). The Defendants filed an answer to Trading Technologies’ amended complaint, as well as related counterclaims. The Defendants deny Trading Technologies’ claims, assert that the asserted patents are not infringed and are invalid, and assert several other defenses as well. Trading Technologies also filed patent infringement lawsuits against approximately a dozen other companies in the same court. The Litigation was consolidated with the other lawsuits filed by Trading Technologies. The Defendants and/or certain codefendants filed petitions with the United States Patent and Trademark Office (“USPTO”) for Covered Business Method Review (“CBM Review”) on the asserted patents. The District Court granted the Defendants’ motion to stay the Litigation pending the CBM Reviews. The USPTO Patent Trial Appeal Board found ten of the twelve asserted patents to be not patentable and two patents to be patentable. The Defendants have filed appeals on the claims that were held to be patentable. It is difficult to predict the outcome of the matter, however, the Company believes it has meritorious defenses to the allegations made in the complaint and intends to defend itself vigorously against them. However, litigation is inherently uncertain and there can be no guarantee that the Company will prevail or that the Litigation can be settled on favorable terms. Class Action Matter On December 18, 2015, a former individual customer filed a purported class action complaint against IB LLC, IBG, Inc., and Thomas Frank, PhD, the Company’s Executive Vice President and Chief Information Officer, in the U.S. District Court for the District of Connecticut. The complaint alleges that the purported class of IB LLC’s customers were harmed by alleged “flaws” in the computerized system used to close out (i.e., liquidate) positions in customer brokerage accounts that have margin deficiencies. The complaint seeks, among other things, undefined compensatory damages and declaratory and injunctive relief. On September 28, 2016, the District Court issued an order granting the Company’s motion to dismiss the complaint in its entirety, and without providing plaintiff leave to amend. On September 28, 2017, plaintiff appealed to the United States Court of Appeals for the Second Circuit. On September 26, 2018, the Court of Appeals affirmed the dismissal of plaintiff’s claims of breach of contract and commercially unreasonable liquidation but vacated and remanded back to the District Court plaintiff’s claims for negligence. The Company expects that further proceedings will take place in the District Court at which the Court will consider whether plaintiff can assert negligence claims under Connecticut law based on the facts alleged. The Company believes that after such proceedings the District Court again will dismiss the negligence claims. Regardless of the ultimate outcome of the motion to dismiss, the Company does not believe that a purported class action is appropriate given the great differences in portfolios, markets and many other circumstances surrounding the liquidation of any particular customer’s margin-deficient account. IB LLC and the related defendants intend to continue to defend themselves vigorously against the case and, consistent with past practice in connection with this type of unwarranted action, any potential claims for counsel fees and expenses incurred in defending the case shall be fully pursued against the plaintiff. Guarantees Certain of the Operating Companies provide guarantees to securities and commodities clearing houses and exchanges which meet the accounting definition of a guarantee under FASB ASC Topic 460, “Guarantees.” Under standard membership agreements, clearing house and exchange members are required to guarantee collectively the performance of other members. Under the agreements, if a member becomes unable to satisfy its obligations, other members would be required to meet shortfalls. In the opinion of management, the Operating Companies’ liability under these arrangements is not quantifiable and could exceed the cash and securities they have posted as collateral. However, the potential for these Operating Companies to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is carried in the condensed consolidated statements of financial condition for these arrangements. In connection with its retail brokerage business, IB LLC or other electronic brokerage Operating Companies perform securities and commodities execution, clearance and settlement on behalf of their customers for whom they commit to settle trades submitted by such customers with the respective clearing houses. If a customer fails to fulfill its settlement obligations, the respective Operating Company must fulfill those settlement obligations. No contingent liability is carried on the condensed consolidated statements of financial condition for such customer obligations. Other Commitments Certain clearing houses, clearing banks and firms used by certain Operating Companies are given a security interest in certain assets of those Operating Companies held by those clearing organizations. These assets may be applied to satisfy the obligations of those Operating Companies to the respective clearing organizations.

12. Commitments, Contingencies and Guarantees

Litigation

The Company is subject to certain pending and threatened legal actions that arise out of the normal course of business. Litigation is inherently unpredictable, particularly in proceedings where claimants seek substantial or indeterminate damages, or which are in their early stages. The Company has not been able to quantify the actual loss or range of loss related to such legal proceedings, the manner in which they will be resolved, the timing of final resolution or the ultimate settlement. Management believes that the resolution of these actions will not have a material effect, if any, on the Company’s business or financial condition, but may have a material impact on the results of operations for a given period.

The Company accounts for potential losses related to litigation in accordance with FASB ASC Topic 450, “Contingencies.” As of September 30, 2018 and 2017, reserves provided for potential losses related to litigation matters were not material.

Trading Technologies Matter

On February 3, 2010, Trading Technologies International, Inc. (“Trading Technologies”) filed a complaint in the U.S. District Court for the Northern District of Illinois, Eastern Division, against IBG, Inc., IBG LLC, Holdings, and IB LLC. Thereafter, Trading Technologies dismissed IBG, Inc. and Holdings from the case, leaving only IBG LLC and IB LLC as defendants (“Defendants”). The operative complaint, as amended, alleges that the Defendants have infringed and continue to infringe twelve U.S. patents held by Trading Technologies. Trading Technologies is seeking, among other things, unspecified damages and injunctive relief (“the Litigation”). The Defendants filed an answer to Trading Technologies’ amended complaint, as well as related counterclaims. The Defendants deny Trading Technologies’ claims, assert that the asserted patents are not infringed and are invalid, and assert several other defenses as well. Trading Technologies also filed patent infringement lawsuits against approximately a dozen other companies in the same court. The Litigation was consolidated with the other lawsuits filed by Trading Technologies.

The Defendants and/or certain codefendants filed petitions with the United States Patent and Trademark Office (“USPTO”) for Covered Business Method Review (“CBM Review”) on the asserted patents. The District Court granted the Defendants’ motion to stay the Litigation pending the CBM Reviews. The USPTO Patent Trial Appeal Board found ten of the twelve asserted patents to be not patentable and two patents to be patentable. The Defendants have filed appeals on the claims that were held to be patentable.

It is difficult to predict the outcome of the matter, however, the Company believes it has meritorious defenses to the allegations made in the complaint and intends to defend itself vigorously against them. However, litigation is inherently uncertain and there can be no guarantee that the Company will prevail or that the Litigation can be settled on favorable terms.

Class Action Matter

On December 18, 2015, a former individual customer filed a purported class action complaint against IB LLC, IBG, Inc., and Thomas Frank, PhD, the Company’s Executive Vice President and Chief Information Officer, in the U.S. District Court for the District of Connecticut. The complaint alleges that the purported class of IB LLC’s customers were harmed by alleged “flaws” in the computerized system used to close out (i.e., liquidate) positions in customer brokerage accounts that have margin deficiencies. The complaint seeks, among other things, undefined compensatory damages and declaratory and injunctive relief.

On September 28, 2016, the District Court issued an order granting the Company’s motion to dismiss the complaint in its entirety, and without providing plaintiff leave to amend. On September 28, 2017, plaintiff appealed to the United States Court of Appeals for the Second Circuit. On September 26, 2018, the Court of Appeals affirmed the dismissal of plaintiff’s claims of breach of contract and commercially unreasonable liquidation but vacated and remanded back to the District Court plaintiff’s claims for negligence. The Company expects that further proceedings will take place in the District Court at which the Court will consider whether plaintiff can assert negligence claims under Connecticut law based on the facts alleged. The Company believes that after such proceedings the District Court again will dismiss the negligence claims. Regardless of the ultimate outcome of the motion to dismiss, the Company does not believe that a purported class action is appropriate given the great differences in portfolios, markets and many other circumstances surrounding the liquidation of any particular customer’s margin-deficient account. IB LLC and the related defendants intend to continue to defend themselves vigorously against the case and, consistent with past practice in connection with this type of unwarranted action, any potential claims for counsel fees and expenses incurred in defending the case shall be fully pursued against the plaintiff.

Guarantees

Certain of the Operating Companies provide guarantees to securities and commodities clearing houses and exchanges which meet the accounting definition of a guarantee under FASB ASC Topic 460, “Guarantees.” Under standard membership agreements, clearing house and exchange members are required to guarantee collectively the performance of other members. Under the agreements, if a member becomes unable to satisfy its obligations, other members would be required to meet shortfalls. In the opinion of management, the Operating Companies’ liability under these arrangements is not quantifiable and could exceed the cash and securities they have posted as collateral. However, the potential for these Operating Companies to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is carried in the condensed consolidated statements of financial condition for these arrangements.

In connection with its retail brokerage business, IB LLC or other electronic brokerage Operating Companies perform securities and commodities execution, clearance and settlement on behalf of their customers for whom they commit to settle trades submitted by such customers with the respective clearing houses. If a customer fails to fulfill its settlement obligations, the respective Operating Company must fulfill those settlement obligations. No contingent liability is carried on the condensed consolidated statements of financial condition for such customer obligations.

Other Commitments

Certain clearing houses, clearing banks and firms used by certain Operating Companies are given a security interest in certain assets of those Operating Companies held by those clearing organizations. These assets may be applied to satisfy the obligations of those Operating Companies to the respective clearing organizations.