Fair Value Of Financial Instruments (Schedule Of Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities purchased under agreements to resell	$ 470,025	$ 217,930
Financial instruments owned	981,282	694,028
Available-for-sale securities	2,190,128	2,230,297
Held-to-maturity securities	4,765,024	4,107,960
Securities sold under agreements to repurchase	208,228	190,955
Financial instruments sold, but not yet purchased, at fair value	644,762	437,978
Senior notes	1,112,672	1,112,409
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,425,511	2,279,274
Cash segregated for regulatory purposes	95,074	172,932
Securities purchased under agreements to resell	470,025	217,930
Financial instruments owned	981,282	694,028
Available-for-sale securities	2,190,128	2,230,297
Held-to-maturity securities	4,761,401	4,117,384
Bank loans	12,091,713	11,006,760
Loans held for sale	330,521	551,248
Investments	119,545	113,862
Securities sold under agreements to repurchase	208,228	190,955
Bank deposits	18,715,133	17,396,497
Financial instruments sold, but not yet purchased, at fair value	644,762	437,978
Senior notes	1,112,672	1,112,409
Debentures to Stifel Financial Capital Trusts	60,000	60,000
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,425,511	2,279,274
Cash segregated for regulatory purposes	95,074	172,932
Securities purchased under agreements to resell	470,025	217,930
Financial instruments owned	981,282	694,028
Available-for-sale securities	2,190,128	2,230,297
Held-to-maturity securities	4,765,024	4,107,960
Bank loans	12,168,119	11,088,058
Loans held for sale	330,521	551,248
Investments	119,545	113,862
Securities sold under agreements to repurchase	208,228	190,955
Bank deposits	18,527,784	17,192,722
Financial instruments sold, but not yet purchased, at fair value	644,762	437,978
Senior notes	1,228,983	1,265,669
Debentures to Stifel Financial Capital Trusts	$ 46,444	$ 41,071

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to regulations other than SEC Regulations and the Commodity Exchange Act.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of obligations incurred from short sales.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Sum of the carrying amounts as of the balance sheet date of all investments.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount, after the effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes purchases of participations in pools of securities that are subject to a resale agreement, assets not subject to a master netting arrangement and not elected to be offset.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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