Fair Value Of Financial Instruments (Estimated Fair Values Of Financial Instruments Not Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities purchased under agreements to resell	[1]	$ 446,766	$ 385,008
Held-to-maturity securities		2,951,742	2,827,883
Securities sold under agreements to repurchase	[2]	219,888	391,634
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		1,740,214	1,116,862
Cash segregated for regulatory purposes		111,017	131,374
Securities purchased under agreements to resell		446,766	385,008
Held-to-maturity securities		2,951,742	2,827,883
Bank loans		10,516,540	9,801,986
Loans held for sale		474,899	389,693
Securities sold under agreements to repurchase		219,888	391,634
Bank deposits		16,055,206	14,467,894
Federal Home Loan Bank advances		323,000	250,000
Senior notes		1,532,955	1,069,425
Debentures to Stifel Financial Capital Trusts		38,360	45,847
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		1,740,214	1,116,862
Cash segregated for regulatory purposes		111,017	131,374
Securities purchased under agreements to resell		395,998	342,132
Securities sold under agreements to repurchase			22,205
Federal Home Loan Bank advances		323,000	250,000
Senior notes		1,532,955	1,069,425
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		50,768	42,876
Held-to-maturity securities		2,811,440	2,666,773
Bank loans		10,516,540	9,801,986
Loans held for sale		474,899	389,693
Securities sold under agreements to repurchase		219,888	369,429
Bank deposits		16,055,206	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		140,302	161,110
Debentures to Stifel Financial Capital Trusts		$ 38,360	$ 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 $447.6 million and $385.3 million at June 30, 2020 and December 31, 2019, respectively.

[2] Collateral pledged includes the fair value of securities pledged by our company to the counterparty. These securities are included in the consolidated statements of financial condition unless we default. Collateral pledged by our company to the counterparty includes U.S. government agency securities, U.S. government securities, and corporate fixed income securities with market values of $227.0 million and $407.3 million at June 30, 2020 and December 31, 2019, respectively