Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, the Company is subject to various claims, lawsuits and other legal proceedings, including reviews, investigations and proceedings by governmental and self-regulatory agencies regarding its business. While the ultimate resolution of these matters cannot presently be determined, the Company does not believe that, taking into account any applicable insurance coverage, any of the pending legal proceedings, including the matters set forth below, could reasonably be expected to have a material adverse effect on its business, financial condition or results of operations. In the normal course of business, the Company enters into agreements with its customers which provide the customers with indemnification rights, including in the event that the electronic marketplaces of the Company infringe upon the intellectual property or other proprietary right of a third party. The Company’s exposure under these agreements is unknown as this would involve estimating future claims against the Company which have not yet occurred. However, based on its experience, the Company expects the risk of a material loss to be remote. The Company has been named as a defendant, along with other financial institutions, in two consolidated antitrust class actions relating to trading practices in United States Treasury securities auctions. The cases were dismissed in March 2021, with the Court granting the Plaintiffs leave to further amend the complaint by no later than May 14, 2021. The plaintiffs filed an amended complaint on or about May 14, 2021, and the Company moved to dismiss the amended complaint on June 14, 2021. By order dated March 31, 2022, the Court granted the Company’s motion and dismissed all of the claims against it in the amended complaint. The Court also denied the plaintiffs’ request for leave to file a further amended complaint. On April 28, 2022, the Plaintiffs filed a Notice of Appeal of the decision and filed their opening brief on the appeal in the United States Court of Appeals for the Second Circuit on August 18, 2022. The Company filed its brief in response on November 17, 2022. Plaintiffs filed their brief in reply in further support of their appeal on December 14, 2022. The parties have requested oral argument on the appeal, which request is currently pending, and no date for oral argument has yet been set. The Company intends to vigorously defend the District Court’s decision on appeal and assert its meritorious defenses to the allegations. Additionally, the Company was dismissed from a class action relating to an interest rate swaps matter in 2017, but that matter continues against the remaining defendant financial institutions. The Company records its best estimate of a loss, including estimated defense costs, when the loss is considered probable and the amount of such loss can be reasonably estimated. Based on its experience, the Company believes that the amount of damages claimed in a legal proceeding is not a meaningful indicator of the potential liability. At this time, the Company cannot reasonably predict the timing or outcomes of, or estimate the amount of loss, or range of loss, if any, related to its pending legal proceedings, including the matters described above, and therefore does not have any contingency reserves established for any of these matters. Revolving Credit Facility On April 8, 2019, the Company entered into a five year, $500.0 million senior secured revolving credit facility (“Credit Facility”) with a syndicate of banks. The Credit Facility was subsequently amended on November 7, 2019. The Credit Facility provides additional borrowing capacity to be used to fund ongoing working capital needs, letters of credit and for general corporate purposes, including potential future acquisitions and expansions. Under the terms of the credit agreement that governs the Credit Facility, borrowings under the Credit Facility bear interest at a rate equal to, at the Company’s option, either (a) a base rate equal to the greatest of (i) the administrative agent’s prime rate, (ii) the federal funds effective rate plus ½ of 1.0% and (iii) one month LIBOR plus 1.0%, in each case plus 0.75%, or (b) LIBOR plus 1.75%, subject to a 0.00% floor. The credit agreement also includes a commitment fee of 0.25% for available but unborrowed amounts and other administrative fees that are payable quarterly. The Credit Facility is available until April 2024, provided the Company is in compliance with all covenants. Financial covenant requirements include maintaining minimum ratios related to interest coverage and leverage. As of both December 31, 2022 and 2021, there were $0.5 million in letters of credit issued under the Revolving Credit Facility and no borrowings outstanding.