Legal Proceedings	12 Months Ended
Dec. 31, 2017
Loss Contingency Information About Litigation Matters [Abstract]
Legal Proceedings	NOTE 18 – Legal Proceedings Our company and its subsidiaries are named in and subject to various proceedings and claims arising primarily from our securities business activities, including lawsuits, arbitration claims, class actions, and regulatory matters. Some of these claims seek substantial compensatory, punitive, or indeterminate damages. Our company and its subsidiaries are also involved in other reviews, investigations, and proceedings by governmental and self-regulatory organizations regarding our business, which may result in adverse judgments, settlements, fines, penalties, injunctions, and other relief. We are contesting allegations in these claims, and we believe that there are meritorious defenses in each of these lawsuits, arbitrations, and regulatory investigations. In view of the number and diversity of claims against our company, the number of jurisdictions in which litigation is pending, and the inherent difficulty of predicting the outcome of litigation and other claims, we cannot state with certainty what the eventual outcome of pending litigation or other claims will be. We have established reserves for potential losses that are probable and reasonably estimable that may result from pending and potential legal actions, investigations, and regulatory proceedings. In many cases, however, it is inherently difficult to determine whether any loss is probable or reasonably possible or to estimate the amount or range of any potential loss, particularly where proceedings may be in relatively early stages or where plaintiffs are seeking substantial or indeterminate damages. Matters frequently need to be more developed before a loss or range of loss can reasonably be estimated. In our opinion, based on currently available information, review with outside legal counsel, and consideration of amounts provided for in our consolidated financial statements with respect to these matters the ultimate resolution of these matters will not have a material adverse impact on our financial position and results of operations. However, resolution of one or more of these matters may have a material effect on the results of operations in any future period, depending upon the ultimate resolution of those matters and depending upon the level of income for such period. For matters where a reserve has not been established and for which we believe a loss is reasonably possible, as well as for matters where a reserve has been recorded but for which an exposure to loss in excess of the amount accrued is reasonably possible, based on currently available information, we believe that such losses will not have a material effect on our consolidated financial statements. Broyles, et al. v. Cantor Fitzgerald & Co. et al. Matter In December 2013, Stone & Youngberg, LLC (“Stone & Youngberg”) was named in an Amended Complaint filed in U.S. District Court for the Middle District of Louisiana alleging fraud on the part of Stone & Youngberg in connection with the 2007 formation of the Collybus CDO, which was manufactured by Cantor Fitzgerald & Co. (“Cantor”) and purchased by Commonwealth Advisors (“CA”) on behalf of several CA funds (the “fund plaintiffs”), as well as in connection with, among other things, Stone & Youngberg’s facilitation of subsequent trades of Collybus CDO securities by CA on behalf of the CA funds during 2007 and 2008. In the Amended Complaint, the fund plaintiffs allege that they lost over $200.0 million during the financial crisis through mismanagement of the CA funds. In addition to the claims asserted against Stone & Youngberg, the Amended Complaint seeks to hold our company and Stifel liable for Stone & Youngberg’s alleged wrongdoing under theories of successor and alter ego liability, arising out of our company’s purchase of the membership interests of Stone & Youngberg in 2011 and the subsequent operation of that business. In a related action, approximately one dozen individual investors (the “individual plaintiffs”) brought a direct action against the Company and other defendants, seeking recessionary damages of approximately $90 million. The court ruled that the individual plaintiffs had no standing to pursue these claims because the CA funds are separately pursuing claims. The individual plaintiffs appealed that decision to the Fifth Circuit. During December 2017, the fund plaintiffs, the individual plaintiffs, our company and our subsidiaries, including Stone & Youngberg, entered into a settlement agreement that resolved all outstanding litigation related to this matter.

NOTE 18 – Legal Proceedings

Our company and its subsidiaries are named in and subject to various proceedings and claims arising primarily from our securities business activities, including lawsuits, arbitration claims, class actions, and regulatory matters. Some of these claims seek substantial compensatory, punitive, or indeterminate damages. Our company and its subsidiaries are also involved in other reviews, investigations, and proceedings by governmental and self-regulatory organizations regarding our business, which may result in adverse judgments, settlements, fines, penalties, injunctions, and other relief. We are contesting allegations in these claims, and we believe that there are meritorious defenses in each of these lawsuits, arbitrations, and regulatory investigations. In view of the number and diversity of claims against our company, the number of jurisdictions in which litigation is pending, and the inherent difficulty of predicting the outcome of litigation and other claims, we cannot state with certainty what the eventual outcome of pending litigation or other claims will be.

We have established reserves for potential losses that are probable and reasonably estimable that may result from pending and potential legal actions, investigations, and regulatory proceedings. In many cases, however, it is inherently difficult to determine whether any loss is probable or reasonably possible or to estimate the amount or range of any potential loss, particularly where proceedings may be in relatively early stages or where plaintiffs are seeking substantial or indeterminate damages. Matters frequently need to be more developed before a loss or range of loss can reasonably be estimated.

In our opinion, based on currently available information, review with outside legal counsel, and consideration of amounts provided for in our consolidated financial statements with respect to these matters the ultimate resolution of these matters will not have a material adverse impact on our financial position and results of operations. However, resolution of one or more of these matters may have a material effect on the results of operations in any future period, depending upon the ultimate resolution of those matters and depending upon the level of income for such period. For matters where a reserve has not been established and for which we believe a loss is reasonably possible, as well as for matters where a reserve has been recorded but for which an exposure to loss in excess of the amount accrued is reasonably possible, based on currently available information, we believe that such losses will not have a material effect on our consolidated financial statements.

Broyles, et al. v. Cantor Fitzgerald & Co. et al. Matter

In December 2013, Stone & Youngberg, LLC (“Stone & Youngberg”) was named in an Amended Complaint filed in U.S. District Court for the Middle District of Louisiana alleging fraud on the part of Stone & Youngberg in connection with the 2007 formation of the Collybus CDO, which was manufactured by Cantor Fitzgerald & Co. (“Cantor”) and purchased by Commonwealth Advisors (“CA”) on behalf of several CA funds (the “fund plaintiffs”), as well as in connection with, among other things, Stone & Youngberg’s facilitation of subsequent trades of Collybus CDO securities by CA on behalf of the CA funds during 2007 and 2008. In the Amended Complaint, the fund plaintiffs allege that they lost over $200.0 million during the financial crisis through mismanagement of the CA funds.

In addition to the claims asserted against Stone & Youngberg, the Amended Complaint seeks to hold our company and Stifel liable for Stone & Youngberg’s alleged wrongdoing under theories of successor and alter ego liability, arising out of our company’s purchase of the membership interests of Stone & Youngberg in 2011 and the subsequent operation of that business.

In a related action, approximately one dozen individual investors (the “individual plaintiffs”) brought a direct action against the Company and other defendants, seeking recessionary damages of approximately $90 million. The court ruled that the individual plaintiffs had no standing to pursue these claims because the CA funds are separately pursuing claims. The individual plaintiffs appealed that decision to the Fifth Circuit.

During December 2017, the fund plaintiffs, the individual plaintiffs, our company and our subsidiaries, including Stone & Youngberg, entered into a settlement agreement that resolved all outstanding litigation related to this matter.