Nature of Operations and Basis Of Presentation (Policies)	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature Of Operations	Nature of Operations Stifel Financial Corp. (the “Company”), through its wholly owned subsidiaries, is principally engaged in retail brokerage; securities trading; investment banking; investment advisory; retail, consumer, and commercial banking; and related financial services. We have offices throughout the United States, with a growing presence in Europe. Our major geographic area of concentration is throughout the United States, with a growing presence in the United Kingdom and Europe. Our company’s principal customers are individual investors, corporations, municipalities, and institutions.
Basis Of Presentation	Basis of Presentation The consolidated financial statements include Stifel Financial Corp. and its wholly owned subsidiaries, principally Stifel, Nicolaus & Company, Incorporated (“Stifel”), Keefe Bruyette & Woods (“KBW”), and Stifel Bank & Trust (“Stifel Bank”). Unless otherwise indicated, the terms “we,” “us,” “our,” or “our company” in this report refer to Stifel Financial Corp. and its wholly owned subsidiaries. The accompanying consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles, which require management to make certain estimates and assumptions that affect the reported amounts. We consider significant estimates, which are most susceptible to change and impacted significantly by judgments, assumptions, and estimates, to be: valuation of financial instruments and investments in partnerships, accrual for contingencies, allowance for loan losses, derivative instruments and hedging activities, fair value of goodwill and intangible assets, provision for income taxes and related tax reserves, and forfeitures associated with stock-based compensation. Actual results could differ from those estimates. Certain amounts from prior periods have been reclassified to conform to the current period’s presentation. The effect of these reclassifications on our company’s previously reported consolidated financial statements was not material.
Consolidation Policies	Consolidation Policies The consolidated financial statements include the accounts of Stifel Financial Corp. and its subsidiaries. We also have investments or interests in other entities for which we must evaluate whether to consolidate by determining whether we have a controlling financial interest or are considered to be the primary beneficiary. In determining whether to consolidate these entities, we evaluate whether the entity is a voting interest entity or a variable interest entity (“VIE”). When we do not have a controlling interest in an entity, but we exert significant influence over the entity, we apply the equity method of accounting. All material intercompany balances and transactions have been eliminated in consolidation.
Voting Interest Entity	Voting Interest Entity – Voting interest entities are entities that have (i) total equity investment at risk sufficient to fund expected future operations independently, and (ii) equity holders who have the obligation to absorb losses or receive residual returns and the right to make decisions about the entity’s activities. We consolidate voting interest entities when we determine that there is a controlling financial interest, usually ownership of all, or a majority of, the voting interest.
Variable Interest Entity	Variable Interest Entity – VIEs are entities that lack one or more of the characteristics of a voting interest entity. We are required to consolidate certain VIEs in which we have the power to direct the activities of the entity and the obligation to absorb significant losses or receive significant benefits. In other cases, we consolidate VIEs when we are deemed to be the primary beneficiary. The primary beneficiary is defined as the entity that has a variable interest, or a combination of variable interests, that maintains control and receives benefits or will absorb losses that are not pro rata with its ownership interests. The determination as to whether an entity is a VIE is based on the structure and nature of the entity. We also consider other characteristics, such as the ability to influence the decision-making relative to the entity’s activities and how the entity is financed. With the exception of entities eligible for the deferral codified in Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) 2010-10, “Consolidation: Amendments for Certain Investment Funds” (“ASU 2010-10”) (generally asset managers and investment companies), ASC 810 states that a controlling financial interest in an entity is present when an enterprise has a variable interest, or combination of variable interests, that have both the power to direct the activities of the entity that most significantly impact the entity’s economic performance and the obligation to absorb losses of the entity or the rights to receive benefits from the entity that could potentially be significant to the entity. Entities meeting the deferral provision defined by ASU 2010-10 are evaluated under the historical VIE guidance. Under the historical guidance, a controlling financial interest in an entity is present when an enterprise has a variable interest, or combination of variable interests, that will absorb a majority of the entity’s expected losses, receive a majority of the entity’s expected residual returns, or both. The enterprise with a controlling financial interest, known as the primary beneficiary, consolidates the VIE. We determine whether we are the primary beneficiary of a VIE by first performing a qualitative analysis of the VIE’s control structure, expected benefits and losses, and expected residual returns. This analysis includes a review of, among other factors, the VIE’s capital structure, contractual terms, which interests create or absorb benefits or losses, variability, related party relationships, and the design of the VIE. Where a qualitative analysis is not conclusive, we perform a quantitative analysis. We reassess our initial evaluation of an entity as a VIE and our initial determination of whether we are the primary beneficiary of a VIE upon the occurrence of certain reconsideration events. See Note 27 for additional information on VIEs.