Regulatory Capital Requirements (Schedule Of Total Risk-Based, Tier 1 Risk-Based, And Tier 1 Leverage Ratios) (Details) $ in Thousands	Jun. 30, 2021 USD ($)
Stifel Financial Corp. [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 3,207,682
Tier 1 capital, Actual Ratio	0.189
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 1,017,145
Tier 1 capital For Capital Adequacy Purposes, Ratio	6.0
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,356,193
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.0
Total capital, Actual Amount	$ 3,353,813
Total capital, Actual Ratio	0.198
Total capital For Capital Adequacy Purposes, Amount	$ 1,356,193
Total capital For Capital Adequacy Purposes, Ratio	8.0
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,695,242
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.0
Tier 1 leverage, Actual Amount	$ 3,207,682
Tier 1 leverage, Actual Ratio	0.117
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 1,095,114
Tier 1 leverage For Capital Adequacy Purposes, Ratio	4.0
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,368,893
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.0
Stifel Financial Corp. [Member] | Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 2,672,682
Tier 1 capital, Actual Ratio	0.158
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 762,859
Tier 1 capital For Capital Adequacy Purposes, Ratio	4.5
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,101,907
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.5
Stifel Bank & Trust [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,069,763
Tier 1 capital, Actual Ratio	0.107
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 597,486
Tier 1 capital For Capital Adequacy Purposes, Ratio	6.0
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 796,648
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.0
Total capital, Actual Amount	$ 1,178,159
Total capital, Actual Ratio	0.118
Total capital For Capital Adequacy Purposes, Amount	$ 796,648
Total capital For Capital Adequacy Purposes, Ratio	8.0
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 995,811
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.0
Tier 1 leverage, Actual Amount	$ 1,069,763
Tier 1 leverage, Actual Ratio	0.070
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 607,050
Tier 1 leverage For Capital Adequacy Purposes, Ratio	4.0
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 758,812
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.0
Stifel Bank & Trust [Member] | Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,069,763
Tier 1 capital, Actual Ratio	0.107
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 448,115
Tier 1 capital For Capital Adequacy Purposes, Ratio	4.5
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 647,277
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.5
Stifel Bank [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 326,622
Tier 1 capital, Actual Ratio	0.205
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 95,638
Tier 1 capital For Capital Adequacy Purposes, Ratio	6.0
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 127,517
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.0
Total capital, Actual Amount	$ 333,440
Total capital, Actual Ratio	0.209
Total capital For Capital Adequacy Purposes, Amount	$ 127,517
Total capital For Capital Adequacy Purposes, Ratio	8.0
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 159,396
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.0
Tier 1 leverage, Actual Amount	$ 326,622
Tier 1 leverage, Actual Ratio	0.071
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 184,951
Tier 1 leverage For Capital Adequacy Purposes, Ratio	4.0
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 231,189
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.0
Stifel Bank [Member] | Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 326,622
Tier 1 capital, Actual Ratio	0.205
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 71,728
Tier 1 capital For Capital Adequacy Purposes, Ratio	4.5
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 103,608
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.5