Regulatory Capital Requirements (Schedule Of Total Risk-Based, Tier 1 Risk-Based, And Tier 1 Leverage Ratios) (Details) $ in Thousands	Sep. 30, 2026 USD ($)	Dec. 31, 2025 USD ($)
Stifel Financial Corp. [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 4,671,343	$ 4,503,450
Tier 1 capital, Actual Ratio	0.17	0.183
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 1,645,842	$ 1,476,179
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.06	0.06
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 2,194,456	$ 1,968,239
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.08	0.08
Total capital, Actual Amount	$ 4,867,806	$ 4,717,659
Total capital, Actual Ratio	0.177	0.192
Total capital For Capital Adequacy Purposes, Amount	$ 2,194,456	$ 1,968,239
Total capital For Capital Adequacy Purposes, Ratio	0.08	0.08
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 2,743,070	$ 2,460,299
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.10	0.10
Tier 1 leverage, Actual Amount	$ 4,671,343	$ 4,503,450
Tier 1 leverage, Actual Ratio	0.108	0.114
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 1,722,402	$ 1,576,603
Tier 1 leverage For Capital Adequacy Purposes, Ratio	0.04	0.04
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 2,153,003	$ 1,970,753
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.05	0.05
Stifel Financial Corp. [Member] \| Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 3,986,343	$ 3,818,450
Tier 1 capital, Actual Ratio	0.145	0.155
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 1,234,381	$ 1,107,134
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.045	0.045
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,782,995	$ 1,599,194
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065	0.065
Stifel Bank & Trust [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,349,295	$ 1,328,266
Tier 1 capital, Actual Ratio	0.11	0.112
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 739,260	$ 712,588
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.06	0.06
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 985,680	$ 950,118
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.08	0.08
Total capital, Actual Amount	$ 1,433,733	$ 1,438,847
Total capital, Actual Ratio	0.116	0.121
Total capital For Capital Adequacy Purposes, Amount	$ 985,680	$ 950,118
Total capital For Capital Adequacy Purposes, Ratio	0.08	0.08
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,232,101	$ 1,187,647
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.10	0.10
Tier 1 leverage, Actual Amount	$ 1,349,295	$ 1,328,266
Tier 1 leverage, Actual Ratio	0.071	0.07
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 759,240	$ 756,723
Tier 1 leverage For Capital Adequacy Purposes, Ratio	0.04	0.04
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 949,050	$ 945,904
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.05	0.05
Stifel Bank & Trust [Member] \| Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,349,295	$ 1,328,266
Tier 1 capital, Actual Ratio	0.11	0.112
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 554,445	$ 534,441
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.045	0.045
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 800,865	$ 771,971
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065	0.065
Stifel Bank [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,088,652	$ 854,826
Tier 1 capital, Actual Ratio	0.111	0.118
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 586,425	$ 433,280
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.06	0.06
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 781,900	$ 577,707
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.08	0.08
Total capital, Actual Amount	$ 1,147,532	$ 905,308
Total capital, Actual Ratio	0.117	0.125
Total capital For Capital Adequacy Purposes, Amount	$ 781,900	$ 577,707
Total capital For Capital Adequacy Purposes, Ratio	0.08	0.08
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 977,374	$ 722,134
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.10	0.10
Tier 1 leverage, Actual Amount	$ 1,088,652	$ 854,826
Tier 1 leverage, Actual Ratio	0.07	0.071
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 619,984	$ 481,165
Tier 1 leverage For Capital Adequacy Purposes, Ratio	0.04	0.04
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 774,980	$ 601,456
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.05	0.05
Stifel Bank [Member] \| Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,088,652	$ 854,826
Tier 1 capital, Actual Ratio	0.111	0.118
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 439,818	$ 324,960
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.045	0.045
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 635,293	$ 469,387
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065	0.065

Amount of total capital as defined by regulatory framework.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-Section 50
-Paragraph 1
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-Publisher FASB
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