Borrowings and Federal Home Loan Bank Advances (Narrative) (Details)	3 Months Ended	9 Months Ended
Sep. 30, 2018 USD ($) item	Sep. 30, 2018 USD ($) item
Short-term Debt [Line Items]
Uncommitted secured lines of credit		$ 1,000,000,000
Number of banks \| item	6	6
Daily borrowings under our uncommitted secured lines	$ 391,000,000	$ 391,000,000
Compensating balances	0	0
Federal home loan advances, floating-rate	1,100,000,000	$ 1,100,000,000
Stifel Bancorp [Member]
Short-term Debt [Line Items]
Notes maturity year		2043
Notes payable	134,800,000	$ 134,800,000
Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Committed revolving credit facility with bank and broker dealer - subsidiary	200,000,000	$ 200,000,000
Credit facility expiration date		2020-03
LIBOR rate		1.75%
Outstanding credit facility	0	$ 0
Stifel Credit Facility [Member]
Short-term Debt [Line Items]
Committed revolving credit facility with bank and broker dealer - subsidiary	250,000,000	$ 250,000,000
Credit facility expiration date		2019-06
Outstanding credit facility	$ 0	$ 0
Credit agreement maturity days		364 days
Company Owned Securities [Member]
Short-term Debt [Line Items]
Uncommitted secured lines of credit		$ 0
Federal Home Loan Bank advances [Member]
Short-term Debt [Line Items]
Weighted average interest rate on borrowings	1.65%	1.52%

Daily borrowings under credit arrangements.

No definition available.

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- Definition

Debt instrument maturity year.

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No definition available.

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- Definition

Line of credit facility expiration days.

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No definition available.

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Line of credit facility expiration month and year.

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No definition available.

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- Definition

Number of banks with which entity has committed revolving credit facility.

+ References

No definition available.

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- Definition

Uncommitted secured lines of credit.

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No definition available.

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- Definition

Weighted average interest rate on borrowings.

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No definition available.

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- Definition

The amount of a specific compensating balance arrangement that is maintained under an agreement for a bank loan or future credit availability.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank) with floating interest rate.

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No definition available.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- Definition

Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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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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