Commitments and Contingencies	3 Months Ended
Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies In the ordinary course of business, the Company from time to time enters into contracts containing indemnification obligations of the Company. These obligations may require the Company to make payments to another party upon the occurrence of certain events including the failure by the Company to meet its performance obligations under the contract. These contractual indemnification provisions are often standard contractual terms of the nature customarily found in the type of contracts entered into by the Company. In many cases, there are no stated or notional amounts included in the indemnification provisions. There are no amounts reflected on the Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020 related to these indemnifications. Stanford Trust Company Litigation SEI has been named in seven lawsuits filed in Louisiana courts; four of the cases also name SPTC as a defendant. The underlying allegations in all actions relate to the purported role of SPTC in providing back-office services to Stanford Trust Company. The complaints allege that SEI and SPTC participated in some manner in the sale of “certificates of deposit” issued by Stanford International Bank so as to be a “seller” of the certificates of deposit for purposes of primary liability under the Louisiana Securities Law or so as to be secondarily liable under that statute for sales of certificates of deposit made by Stanford Trust Company. Two of the actions also include claims for violations of the Louisiana Racketeering Act and possibly conspiracy, and a third also asserts claims of negligence, breach of contract, breach of fiduciary duty, violations of the uniform fiduciaries law, negligent misrepresentation, detrimental reliance, violations of the Louisiana Racketeering Act, and conspiracy. The procedural status of the seven cases varies. The Lillie case, filed originally in the 19th Judicial District Court for the Parish of East Baton Rouge, was brought as a class action. A group of plaintiffs who opted out of the Lillie class filed a complaint against SEI and SPTC in the United States District Court in the Middle District of Louisiana, alleging claims essentially the same as those in Lillie. In both cases, as a result of the proceedings in the Northern District of Texas, only the plaintiffs’ secondary liability claims under Section 714(B) of the Louisiana Securities Law remain. On January 31, 2019, the Judicial Panel on Multidistrict Litigation remanded the Lillie and Ahders proceedings to the Middle District of Louisiana. With respect to the Lillie proceeding, on July 9, 2019, the District Court issued an order granting SEI’s Summary Judgment Motion to dismiss the remaining Section 714(B) claim and denying Plaintiffs’ Motion for Continuance of SEI and SPTC’s Motion for Summary Judgment pursuant to Rule 56(d). On August 27, 2019, Plaintiffs-Appellants filed a Notice of Appeal to the United States Court of Appeals for the Fifth Circuit of the District Court's dismissal of the Lillie matter. The parties are currently scheduled to present oral arguments on the Plaintiffs-Appellants' motion for appeal on April 26, 2021. With respect to the Ahders proceeding, on January 24, 2020, the District Court issued an order granting SEI’s Summary Judgment Motion to dismiss the remaining Section 714(B) claim. On March 17, 2020, Plaintiffs-Appellants filed a Notice of Appeal to the United States Court of Appeals for the Fifth Circuit of the District Court's dismissal of the Ahders matter. On December 3, 2020, the United States Court of Appeals for the Fifth Circuit unanimously affirmed the District Court’s order granting summary judgment in favor of SEI and the Insurer Defendants in the Adhers matter. Another case, filed in the 23rd Judicial District Court for the Parish of Ascension, also was removed to federal court and transferred by the Judicial Panel on Multidistrict Litigation to the Northern District of Texas and the Stanford Multidistrict Litigation (MDL). The schedule for responding to that Complaint has not yet been established. Two additional cases remain in the Parish of East Baton Rouge. Plaintiffs filed petitions in 2010 and have granted SEI and SPTC indefinite extensions to respond. No material activity has taken place since. In two additional cases, filed in East Baton Rouge and brought by the same counsel who filed the Lillie action, virtually all of the litigation to date has involved motions practice and appellate litigation regarding the existence of federal subject matter jurisdiction under the federal Securities Litigation Uniform Standards Act (SLUSA). The matters were removed to the United States District Court for the Northern District of Texas and consolidated. The court then dismissed the action under SLUSA. The Court of Appeals for the Fifth Circuit reversed that order, and the Supreme Court of the United States affirmed the Court of Appeals judgment on February 26, 2014. The matters were remanded to state court and no material activity has taken place since that date. While the outcome of this litigation remains uncertain, SEI and SPTC believe that they have valid defenses to plaintiffs' claims and intend to defend the lawsuits vigorously. Because of uncertainty in the make-up of the Lillie class, the specific theories of liability that may survive a motion for summary judgment or other dispositive motion, the relative lack of discovery regarding damages, causation, mitigation and other aspects that may ultimately bear upon loss, the Company is not reasonably able to provide an estimate of loss, if any, with respect to the foregoing lawsuits. SS&C Advent Litigation On February 28, 2020, SEI Global Services, Inc. (SGSI), a wholly-owned subsidiary of the Company, filed a complaint under seal in the United States District Court for the Eastern District of Pennsylvania against SS&C Advent (Advent) and SS&C Technologies Holdings, Inc. (SS&C) alleging that SS&C and Advent breached the terms of the contract between the parties and asking the Court to hold SS&C and Advent to their bargained-for obligations (the Advent Matter). In addition to Breach of Contract, the complaint also includes counts for Declaratory Judgment, Tortious Interference with Existing and Prospective Contractual Relations, Violation of the New York General Business Law Section 349, Violations of Section 2 of the Sherman Antitrust Act, Promissory Estoppel and Breach of the Covenant of Good Faith and Fair Dealing. SGSI seeks various forms of relief, including declaratory judgment, specific performance under the contract, and monetary damages, including treble damages and attorney’s fees. Following various procedural actions, including an amendment of SGSI’s complaint to include additional breach of contract claims, Advent filed a motion to dismiss SGSI’s compliant. On October 23, 2020, the United States District Court for the Eastern District of Pennsylvania dismissed SEI’s federal anti-trust claims and declined to rule on the state law claims on the basis that in the absence of the anti-trust claim, the court had no jurisdiction over the state law claims. SGSI has appealed the dismissal of the federal anti-trust claims to the Third Circuit Court of Appeals, which is currently pending. Upon the dismissal of the federal anti-trust claim, on October 23, 2020, each of Advent and SGSI filed competing lawsuits in New York and Pennsylvania, respectively, to litigate the remaining breach of contract and tortious interference with contract claims. Additionally, SGSI made motions for injunctive relief to insure that Advent provided SGSI with access to the Geneva, Moxy and APX software modules as SGSI believes is required pursuant to the terms of a valid contract. Although SGSI had the right to litigate the matter in the Pennsylvania Commonwealth courts, critical timing imperatives related to access to the relevant software led SGSI to consent to the jurisdiction of the New York courts and litigate the matter as the defendant in New York State courts. There is no material difference in the claims, defenses, or burdens of proof for either of Advent, as the plaintiff, or SGSI, as defendant, in New York courts, or in Pennsylvania with the roles of plaintiff and defendant reversed. On January 13, 2021, Judge Borrok of the Supreme Court of the State of New York, granted SGSI’s motion for injunctive relief and issued an Order in which he characterized the basis for Advent’s claim for breach of contract as appearing to be “pre-textual” and found that SGSI’s claims for breach of contract would likely succeed on the merits. Judge Borrok granted SGSI’s motion for injunctive relief, on a preliminary basis, and precluded SS&C Advent from: •Dishonoring their contractual obligations and commitments under the SLSA, including, denying SEI’s licenses, rights, and privileges under the SLSA; •Failing to provide new license keys for the license keys due to Geneva, Moxy, and APX, and other software products licensed by SEI pursuant to the SLSA (such new license keys to be provided no later than January 15, 2021 at 10 A.M.); •Denying to SEI any and all access to the Geneva, Moxy, and APX software and related modules as are reasonably necessary to provide access to such software to SEI’s clients; and •Denying to SEI any and all support, maintenance and technical support services for Geneva, Moxy, and APX. SS&C Advent provided SEI with the necessary access to the Geneva, Moxy and APX software modules on January 14, 2021. These have been tested, verified and are now running in the SEI production environment. On January 15, 2021, SS&C Advent appealed Judge Borrok’s order granting SEI’s motion for preliminary injunctive relief to the Appellate Division of the Supreme Court of the State of New York, First Department. The parties are beginning discovery and participating in a voluntary mediation moderated by Judge Borrok that is scheduled for May 27, 2021. SEI does not believe that it will have to change providers under the current terms of its contract with SS&C Advent and that the process of litigating its rights under this contract may be a multi-year process. Consequently, SEI does not believe that the Advent Matter will create any consequence to the services SGSI provides to its clients in the near term. SEI believes that it has alternatives available to it that will enable it to continue to provide currently provided services to its clients in all material respects in the unlikely event that there ultimately is a negative outcome in the Advent Matter. SEI believes SGSI has a strong basis for proving the actions it alleges in the Advent Matter and looks forward to the opportunity to continue to assert its rights under contract. SEI expects the financial impact of litigating the Advent Matter to be immaterial. Other Matters The Company is also a party to various other actions and claims arising in the normal course of business that the Company does not believe are material. The Company believes that the ultimate resolution of these matters will not have a material adverse effect on the Company's financial position or the manner in which the Company conducts its business. Currently, the Company does not believe the amount of losses associated with these matters can be estimated. While the Company does not believe that the amount of such losses will, when liquidated or estimable, be material to its financial position, the assumptions may be incorrect and any such loss could have a material adverse effect on the Company's results of operations or the manner in which the Company conducts its business in the period(s) during which the underlying matters are resolved.

In the ordinary course of business, the Company from time to time enters into contracts containing indemnification obligations of the Company. These obligations may require the Company to make payments to another party upon the occurrence of certain events including the failure by the Company to meet its performance obligations under the contract. These contractual indemnification provisions are often standard contractual terms of the nature customarily found in the type of contracts entered into by the Company. In many cases, there are no stated or notional amounts included in the indemnification provisions. There are no amounts reflected on the Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020 related to these indemnifications.

SEI has been named in seven lawsuits filed in Louisiana courts; four of the cases also name SPTC as a defendant. The underlying allegations in all actions relate to the purported role of SPTC in providing back-office services to Stanford Trust Company. The complaints allege that SEI and SPTC participated in some manner in the sale of “certificates of deposit” issued by Stanford International Bank so as to be a “seller” of the certificates of deposit for purposes of primary liability under the Louisiana Securities Law or so as to be secondarily liable under that statute for sales of certificates of deposit made by Stanford Trust Company. Two of the actions also include claims for violations of the Louisiana Racketeering Act and possibly conspiracy, and a third also asserts claims of negligence, breach of contract, breach of fiduciary duty,

The procedural status of the seven cases varies. The Lillie case, filed originally in the 19th Judicial District Court for the Parish of East Baton Rouge, was brought as a class action. A group of plaintiffs who opted out of the Lillie class filed a complaint against SEI and SPTC in the United States District Court in the Middle District of Louisiana, alleging claims essentially the same as those in Lillie. In both cases, as a result of the proceedings in the Northern District of Texas, only the plaintiffs’ secondary liability claims under Section 714(B) of the Louisiana Securities Law remain. On January 31, 2019, the Judicial Panel on Multidistrict Litigation remanded the Lillie and Ahders proceedings to the Middle District of Louisiana.

With respect to the Lillie proceeding, on July 9, 2019, the District Court issued an order granting SEI’s Summary Judgment Motion to dismiss the remaining Section 714(B) claim and denying Plaintiffs’ Motion for Continuance of SEI and SPTC’s Motion for Summary Judgment pursuant to Rule 56(d). On August 27, 2019, Plaintiffs-Appellants filed a Notice of Appeal to the United States Court of Appeals for the Fifth Circuit of the District Court's dismissal of the Lillie matter. The parties are currently scheduled to present oral arguments on the Plaintiffs-Appellants' motion for appeal on April 26, 2021.

With respect to the Ahders proceeding, on January 24, 2020, the District Court issued an order granting SEI’s Summary Judgment Motion to dismiss the remaining Section 714(B) claim. On March 17, 2020, Plaintiffs-Appellants filed a Notice of Appeal to the United States Court of Appeals for the Fifth Circuit of the District Court's dismissal of the Ahders matter. On December 3, 2020, the United States Court of Appeals for the Fifth Circuit unanimously affirmed the District Court’s order granting summary judgment in favor of SEI and the Insurer Defendants in the Adhers matter.

Another case, filed in the 23rd Judicial District Court for the Parish of Ascension, also was removed to federal court and transferred by the Judicial Panel on Multidistrict Litigation to the Northern District of Texas and the Stanford Multidistrict Litigation (MDL). The schedule for responding to that Complaint has not yet been established.

Two additional cases remain in the Parish of East Baton Rouge. Plaintiffs filed petitions in 2010 and have granted SEI and SPTC indefinite extensions to respond. No material activity has taken place since.

In two additional cases, filed in East Baton Rouge and brought by the same counsel who filed the Lillie action, virtually all of the litigation to date has involved motions practice and appellate litigation regarding the existence of federal subject matter jurisdiction under the federal Securities Litigation Uniform Standards Act (SLUSA). The matters were removed to the United States District Court for the Northern District of Texas and consolidated. The court then dismissed the action under SLUSA. The Court of Appeals for the Fifth Circuit reversed that order, and the Supreme Court of the United States affirmed the Court of Appeals judgment on February 26, 2014. The matters were remanded to state court and no material activity has taken place since that date.

While the outcome of this litigation remains uncertain, SEI and SPTC believe that they have valid defenses to plaintiffs' claims and intend to defend the lawsuits vigorously. Because of uncertainty in the make-up of the Lillie class, the specific theories of liability that may survive a motion for summary judgment or other dispositive motion, the relative lack of discovery regarding damages, causation, mitigation and other aspects that may ultimately bear upon loss, the Company is not reasonably able to provide an estimate of loss, if any, with respect to the foregoing lawsuits.

On February 28, 2020, SEI Global Services, Inc. (SGSI), a wholly-owned subsidiary of the Company, filed a complaint under seal in the United States District Court for the Eastern District of Pennsylvania against SS&C Advent (Advent) and SS&C Technologies Holdings, Inc. (SS&C) alleging that SS&C and Advent breached the terms of the contract between the parties and asking the Court to hold SS&C and Advent to their bargained-for obligations (the Advent Matter). In addition to Breach of Contract, the complaint also includes counts for Declaratory Judgment, Tortious Interference with Existing and Prospective Contractual Relations, Violation of the New York General Business Law Section 349, Violations of Section 2 of the Sherman Antitrust Act, Promissory Estoppel and Breach of the Covenant of Good Faith and Fair Dealing. SGSI seeks various forms of relief, including declaratory judgment, specific performance under the contract, and monetary damages, including treble damages and attorney’s fees.

On October 23, 2020, the United States District Court for the Eastern District of Pennsylvania dismissed SEI’s federal anti-trust claims and declined to rule on the state law claims on the basis that in the absence of the anti-trust claim, the court had no jurisdiction over the state law claims. SGSI has appealed the dismissal of the federal anti-trust claims to the Third Circuit Court of Appeals, which is currently pending.

Upon the dismissal of the federal anti-trust claim, on October 23, 2020, each of Advent and SGSI filed competing lawsuits in New York and Pennsylvania, respectively, to litigate the remaining breach of contract and tortious interference with contract claims. Additionally, SGSI made motions for injunctive relief to insure that Advent provided SGSI with access to the Geneva, Moxy and APX software modules as SGSI believes is required pursuant to the terms of a valid contract. Although SGSI had the right to litigate the matter in the Pennsylvania Commonwealth courts, critical timing imperatives related to access to the relevant software led SGSI to consent to the jurisdiction of the New York courts and litigate the matter as the defendant in New York State courts. There is no material difference in the claims, defenses, or burdens of proof for either of Advent, as the plaintiff, or SGSI, as defendant, in New York courts, or in Pennsylvania with the roles of plaintiff and defendant reversed.

On January 13, 2021, Judge Borrok of the Supreme Court of the State of New York, granted SGSI’s motion for injunctive relief and issued an Order in which he characterized the basis for Advent’s claim for breach of contract as appearing to be “pre-textual” and found that SGSI’s claims for breach of contract would likely succeed on the merits. Judge Borrok granted SGSI’s motion for injunctive relief, on a preliminary basis, and precluded SS&C Advent from:

•Failing to provide new license keys for the license keys due to Geneva, Moxy, and APX, and other software products licensed by SEI pursuant to the SLSA (such new license keys to be provided no later than January 15, 2021 at 10 A.M.);

SS&C Advent provided SEI with the necessary access to the Geneva, Moxy and APX software modules on January 14, 2021. These have been tested, verified and are now running in the SEI production environment.

On January 15, 2021, SS&C Advent appealed Judge Borrok’s order granting SEI’s motion for preliminary injunctive relief to the Appellate Division of the Supreme Court of the State of New York, First Department.

SEI does not believe that it will have to change providers under the current terms of its contract with SS&C Advent and that the process of litigating its rights under this contract may be a multi-year process. Consequently, SEI does not believe that the Advent Matter will create any consequence to the services SGSI provides to its clients in the near term. SEI believes that it has alternatives available to it that will enable it to continue to provide currently provided services to its clients in all material respects in the unlikely event that there ultimately is a negative outcome in the Advent Matter.

SEI believes SGSI has a strong basis for proving the actions it alleges in the Advent Matter and looks forward to the opportunity to continue to assert its rights under contract. SEI expects the financial impact of litigating the Advent Matter to be immaterial.

The Company is also a party to various other actions and claims arising in the normal course of business that the Company does not believe are material. The Company believes that the ultimate resolution of these matters will not have a material adverse effect on the Company's financial position or the manner in which the Company conducts its business. Currently, the Company does not believe the amount of losses associated with these matters can be estimated. While the Company does not believe that the amount of such losses will, when liquidated or estimable, be material to its financial position, the assumptions may be incorrect and any such loss could have a material adverse effect on the Company's results of operations or the manner in which the Company conducts its business in the period(s) during which the underlying matters are resolved.