Nature of Operations, Basis of Presentation, and Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2019
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 and 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. On January 2, 2019, the Company completed the acquisition of First Empire Holding Corp. (“First Empire”) and its subsidiaries, including First Empire Securities, Inc., an institutional broker-dealer specializing in the fixed income markets. See Note 8 in the notes to consolidated financial statements for more details. Pro forma information is not presented, because the acquisition is not considered to be material, as defined by the SEC. The results of operations of First Empire have been included in our results prospectively from the date of acquisition.
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, Inc., and Stifel Bancorp, Inc. (“Stifel Bancorp”). Unless otherwise indicated, the terms “we,” “us,” “our,” or “our company” in this report refer to Stifel Financial Corp. and its wholly owned subsidiaries. We have prepared the accompanying unaudited consolidated financial statements pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Pursuant to these rules and regulations, we have omitted certain information and footnote disclosures we normally include in our annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles. In management’s opinion, we have made all adjustments (consisting only of normal, recurring adjustments, except as otherwise noted) necessary to fairly present our financial position, results of operations and cash flows. Our interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and the notes thereto in our Annual Report on Form 10-K for the year ended December 31, 2018 on file with the SEC. 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. All material intercompany balances and transactions have been eliminated in consolidation. For consolidated subsidiaries that are less than wholly owned, the third-party holdings of equity interests are referred to as non-controlling interests. The portion of shareholders’ equity that is attributable to non-controlling interests for such subsidiaries is presented as non-controlling interests, a component of total equity, in the consolidated statements of financial condition. Our non-controlling interest represents a 27.5% third-party ownership of North Shore Aviation Holdings LLC (“North Shore”), a wholly owned subsidiary of the Company, that through its subsidiary owns airplane engines. 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. See Note 25 for additional information on VIEs.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies For a detailed discussion about the Company’s significant accounting policies, see Note 2, Summary of Significant Accounting Policies, in our consolidated financial statements included in Part II, Item 8 of our Annual Report on Form 10-K for the year ended December 31, 2018. During the three months ended March 31, 2019, other than the following, there were no significant changes made to the Company’s significant accounting policies. The accounting policy changes are attributable to the adoption of the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2016-02, “Leases” (the “new lease standard” or “ASU 2016-02”) on January 1, 2019. These lease policy updates are applied prospectively in our consolidated financial statements from January 1, 2019. Reported financial information for the historical comparable period was not revised and continues to be reported under the accounting standards in effect during the historical periods.
Operating Leases	Operating Leases Our company enters into operating leases for real estate, office equipment and other assets, substantially all of which are used in connection with its operations. We adopted ASU 2016-02 on January 1, 2019, which required our company to recognize, for leases longer than one year, a right-of-use asset representing the right to use the underlying asset for the lease term, and a lease liability representing the liability to make payments. The lease term is generally determined based on the contractual maturity of the lease. For leases where our company has the option to terminate or extend the lease, an assessment of the likelihood of exercising the option is incorporated into the determination of the lease term. Such assessment is initially performed at the inception of the lease and is updated if events occur that impact the original assessment. An operating lease right-of-use asset is initially determined based on the operating lease liability, adjusted for initial direct costs, lease incentives and amounts paid at or prior to lease commencement. This amount is then amortized over the lease term. See Note 17 for information about operating leases. For leases where our company ceased using the space and management has concluded that it will not derive any future economic benefits, we record an impairment of right-of-use assets.

Nature of Operations, Basis of Presentation, and Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

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 and 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.

On January 2, 2019, the Company completed the acquisition of First Empire Holding Corp. (“First Empire”) and its subsidiaries, including First Empire Securities, Inc., an institutional broker-dealer specializing in the fixed income markets. See Note 8 in the notes to consolidated financial statements for more details.

Pro forma information is not presented, because the acquisition is not considered to be material, as defined by the SEC. The results of operations of First Empire have been included in our results prospectively from the date of acquisition.

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, Inc., and Stifel Bancorp, Inc. (“Stifel Bancorp”). Unless otherwise indicated, the terms “we,” “us,” “our,” or “our company” in this report refer to Stifel Financial Corp. and its wholly owned subsidiaries.

We have prepared the accompanying unaudited consolidated financial statements pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Pursuant to these rules and regulations, we have omitted certain information and footnote disclosures we normally include in our annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles. In management’s opinion, we have made all adjustments (consisting only of normal, recurring adjustments, except as otherwise noted) necessary to fairly present our financial position, results of operations and cash flows. Our interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and the notes thereto in our Annual Report on Form 10-K for the year ended December 31, 2018 on file with the SEC.

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

The consolidated financial statements include the accounts of Stifel Financial Corp. and its subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation. For consolidated subsidiaries that are less than wholly owned, the third-party holdings of equity interests are referred to as non-controlling interests. The portion of shareholders’ equity that is attributable to non-controlling interests for such subsidiaries is presented as non-controlling interests, a component of total equity, in the consolidated statements of financial condition.

Our non-controlling interest represents a 27.5% third-party ownership of North Shore Aviation Holdings LLC (“North Shore”), a wholly owned subsidiary of the Company, that through its subsidiary owns airplane engines.

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. See Note 25 for additional information on VIEs.

Summary of Significant Accounting Policies

For a detailed discussion about the Company’s significant accounting policies, see Note 2, Summary of Significant Accounting Policies, in our consolidated financial statements included in Part II, Item 8 of our Annual Report on Form 10-K for the year ended December 31, 2018.

During the three months ended March 31, 2019, other than the following, there were no significant changes made to the Company’s significant accounting policies. The accounting policy changes are attributable to the adoption of the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2016-02, “Leases” (the “new lease standard” or “ASU 2016-02”) on January 1, 2019. These lease policy updates are applied prospectively in our consolidated financial statements from January 1, 2019. Reported financial information for the historical comparable period was not revised and continues to be reported under the accounting standards in effect during the historical periods.

Operating Leases

Our company enters into operating leases for real estate, office equipment and other assets, substantially all of which are used in connection with its operations. We adopted ASU 2016-02 on January 1, 2019, which required our company to recognize, for leases longer than one year, a right-of-use asset representing the right to use the underlying asset for the lease term, and a lease liability representing the liability to make payments. The lease term is generally determined based on the contractual maturity of the lease. For leases where our company has the option to terminate or extend the lease, an assessment of the likelihood of exercising the option is incorporated into the determination of the lease term. Such assessment is initially performed at the inception of the lease and is updated if events occur that impact the original assessment.

An operating lease right-of-use asset is initially determined based on the operating lease liability, adjusted for initial direct costs, lease incentives and amounts paid at or prior to lease commencement. This amount is then amortized over the lease term. See Note 17 for information about operating leases.

For leases where our company ceased using the space and management has concluded that it will not derive any future economic benefits, we record an impairment of right-of-use assets.