Regulatory Capital Requirements (Schedule Of Total Risk-Based, Tier 1 Risk-Based, And Tier 1 Leverage Ratios) (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Stifel Financial Corp. [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 capital, Actual Amount	$ 3,033,655
Tier 1 capital, Actual Ratio	0.194
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 939,359
Tier 1 capital For Capital Adequacy Purposes, Ratio	6.0
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,252,479
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.0
Total capital, Actual Amount	$ 3,184,779
Total capital, Actual Ratio	0.203
Total capital For Capital Adequacy Purposes, Amount	$ 1,252,479
Total capital For Capital Adequacy Purposes, Ratio	8.0
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,565,598
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.0
Tier 1 leverage, Actual Amount	$ 3,033,655
Tier 1 leverage, Actual Ratio	0.115
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 1,056,763
Tier 1 leverage For Capital Adequacy Purposes, Ratio	4.0
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,320,954
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	$ 2,498,655
Tier 1 capital, Actual Ratio	0.160
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 704,519
Tier 1 capital For Capital Adequacy Purposes, Ratio	4.5
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 1,017,639
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	$ 1,044,894
Tier 1 capital, Actual Ratio	0.111
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 565,694
Tier 1 capital For Capital Adequacy Purposes, Ratio	6.0
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 754,259
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.0
Total capital, Actual Amount	$ 1,164,585
Total capital, Actual Ratio	0.124
Total capital For Capital Adequacy Purposes, Amount	$ 754,259
Total capital For Capital Adequacy Purposes, Ratio	8.0
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 942,824
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.0
Tier 1 leverage, Actual Amount	$ 1,044,894
Tier 1 leverage, Actual Ratio	0.071
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 590,236
Tier 1 leverage For Capital Adequacy Purposes, Ratio	4.0
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 737,795
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	$ 1,044,894
Tier 1 capital, Actual Ratio	0.111
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 424,271
Tier 1 capital For Capital Adequacy Purposes, Ratio	4.5
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 612,836
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	$ 280,718
Tier 1 capital, Actual Ratio	0.185
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 91,039
Tier 1 capital For Capital Adequacy Purposes, Ratio	6.0
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 121,385
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.0
Total capital, Actual Amount	$ 291,823
Total capital, Actual Ratio	0.192
Total capital For Capital Adequacy Purposes, Amount	$ 121,385
Total capital For Capital Adequacy Purposes, Ratio	8.0
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 151,731
Total capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.0
Tier 1 leverage, Actual Amount	$ 280,718
Tier 1 leverage, Actual Ratio	0.073
Tier 1 leverage For Capital Adequacy Purposes, Amount	$ 154,213
Tier 1 leverage For Capital Adequacy Purposes, Ratio	4.0
Tier 1 leverage To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 192,766
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	$ 280,718
Tier 1 capital, Actual Ratio	0.185
Tier 1 capital For Capital Adequacy Purposes, Amount	$ 68,279
Tier 1 capital For Capital Adequacy Purposes, Ratio	4.5
Tier 1 capital To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 98,625
Tier 1 To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.5