Regulatory Capital Requirements (Schedule Of Total Risk-Based, Tier 1 Risk-Based, And Tier 1 Leverage Ratios) (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Stifel Financial Corp. [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 2,926,296
Tier 1 capital, Actual Ratio	0.202
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 869,390
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.060
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,159,186
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.080
Total capital, Actual Amount	$ 3,080,234
Total capital, Actual Ratio	0.213
Total capital For Capital Adequacy Purposes, Amount	$ 1,159,186
Total capital For Capital Adequacy Purposes, Ratio	0.080
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,448,983
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.100
Tier 1 leverage, Actual Amount	$ 2,926,296
Tier 1 leverage, Actual Ratio	0.119
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 984,215
Tier 1 leverage For Capital Adequacy Purposes, Ratio	0.040
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,230,269
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.050
Stifel Financial Corp. [Member] | Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 2,391,296
Tier 1 capital, Actual Ratio	0.165
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 652,042
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.045
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 941,839
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065
Stifel Bank & Trust [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,029,659
Tier 1 capital, Actual Ratio	0.114
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 539,675
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.060
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 719,567
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.080
Total capital, Actual Amount	$ 1,142,093
Total capital, Actual Ratio	0.127
Total capital For Capital Adequacy Purposes, Amount	$ 719,567
Total capital For Capital Adequacy Purposes, Ratio	0.080
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 899,459
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.100
Tier 1 leverage, Actual Amount	$ 1,029,659
Tier 1 leverage, Actual Ratio	0.071
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 576,387
Tier 1 leverage For Capital Adequacy Purposes, Ratio	0.040
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 720,483
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.050
Stifel Bank & Trust [Member] | Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 1,029,659
Tier 1 capital, Actual Ratio	0.114
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 404,757
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.045
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 584,648
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065
Stifel Bank [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 209,795
Tier 1 capital, Actual Ratio	0.165
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 76,163
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.060
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 101,550
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.080
Total capital, Actual Amount	$ 224,281
Total capital, Actual Ratio	0.177
Total capital For Capital Adequacy Purposes, Amount	$ 101,550
Total capital For Capital Adequacy Purposes, Ratio	0.080
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 126,938
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.100
Tier 1 leverage, Actual Amount	$ 209,795
Tier 1 leverage, Actual Ratio	0.073
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 114,655
Tier 1 leverage For Capital Adequacy Purposes, Ratio	0.040
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 143,319
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.050
Stifel Bank [Member] | Common Stock [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 209,795
Tier 1 capital, Actual Ratio	0.165
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 57,122
Tier 1 capital For Capital Adequacy Purposes, Ratio	0.045
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 82,510
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065