Regulatory Capital Requirements (Narrative) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Stifel Financial Corp. [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Net capital under the alternative method	$ 1.0
Aggregate debit balances	2.00%
Our Other Broker-Dealer Subsidiaries
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Ratio of indebtedness to net capital	15
Stifel Nicolaus [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Aggregate debit balances	18.60%
Net capital	$ 273.0
Excess of minimum required net capital	$ 243.6

Percentage of aggregate debit balances.

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- Definition

The amount of net capital in excess of the alternative minimum required net capital.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

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- Definition

Amount of net capital requirement computed under the alternative method allowed under regulatory reporting requirements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

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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.

+ References

No definition available.

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- Definition

Net capital is equal to the net worth of the broker dealer, less certain items such as exchange memberships, carrying value of securities not readily marketable, haircuts on marketable securities in proprietary accounts, furniture and equipment and other illiquid assets as defined.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

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- Definition

Indebtedness divided by net capital.

+ References

No definition available.

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