Fair Value Of Financial Instruments (Estimated Fair Values Of Financial Instruments Not Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities purchased under agreements to resell	[1]	$ 217,930	$ 385,008
Held-to-maturity securities		4,107,960	2,827,883
Securities sold under agreements to repurchase	[2]	190,955	391,634
Federal Home Loan Bank advances		0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		2,245,082	1,116,862
Cash segregated for regulatory purposes		172,932	131,374
Securities purchased under agreements to resell		217,930	385,008
Held-to-maturity securities		4,107,960	2,827,883
Bank loans		11,088,058	9,801,986
Loans held for sale		551,248	389,693
Securities sold under agreements to repurchase		190,955	391,634
Bank deposits		17,192,722	14,467,894
Senior notes		1,265,669	1,069,425
Debentures to Stifel Financial Capital Trusts		41,071	45,847
Federal Home Loan Bank advances			250,000
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		2,245,082	1,116,862
Cash segregated for regulatory purposes		172,932	131,374
Securities purchased under agreements to resell		164,094	342,132
Securities sold under agreements to repurchase			22,205
Senior notes		1,265,669	1,069,425
Federal Home Loan Bank advances			250,000
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities purchased under agreements to resell		53,836	42,876
Held-to-maturity securities		3,943,944	2,666,773
Bank loans		11,088,058	9,801,986
Loans held for sale		551,248	389,693
Securities sold under agreements to repurchase		190,955	369,429
Bank deposits		17,192,722	14,467,894
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity securities		164,016	161,110
Debentures to Stifel Financial Capital Trusts		$ 41,071	$ 45,847

[1] Collateral received includes securities received by our company from the counterparty. These securities are not included on the consolidated statements of financial condition unless there is an event of default. The fair value of securities pledged as collateral was $217.3 million and $385.3 million at December 31, 2020 and 2019, respectively.

[2] Collateral pledged includes the fair value of securities pledged by our company to the counter party. These securities are included on the consolidated statements of financial condition unless we default. Collateral pledged by our company to the counter party includes U.S. government agency securities, U.S. government securities, and corporate fixed income securities with market values of $200.2 million and $407.3 million at December 31, 2020 and 2019, respectively.