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, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities purchased under agreements to resell	[1]	$ 699,900	$ 512,220
Held-to-maturity securities	[2]	4,122,907	3,710,478
Securities sold under agreements to repurchase	[3]	535,394	233,704
Bank deposits		15,863,613	13,411,935
Borrowings		180,655	256,000
Senior notes		1,015,973	1,014,940
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		1,916,841	618,842
Cash segregated for regulatory purposes		132,814	90,802
Securities purchased under agreements to resell		699,900	512,220
Held-to-maturity securities		4,122,907	3,710,478
Loans held for sale		205,557	226,068
Bank loans		8,565,347	6,953,328
Securities sold under agreements to repurchase		535,394	233,704
Bank deposits		14,661,996	12,702,746
Federal Home Loan Bank advances		540,000	745,000
Borrowings		180,655	256,000
Senior notes		989,790	1,044,768
Debentures to Stifel Financial Capital Trusts		49,747	64,962
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		1,916,841	618,842
Cash segregated for regulatory purposes		132,814	90,802
Securities purchased under agreements to resell		645,632	428,740
Securities sold under agreements to repurchase		87,273	92,278
Federal Home Loan Bank advances		540,000	745,000
Borrowings		180,655	256,000
Senior notes		989,790	1,044,768
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		54,268	83,480
Held-to-maturity securities		3,960,099	3,517,781
Loans held for sale		205,557	226,068
Bank loans		8,565,347	6,953,328
Securities sold under agreements to repurchase		448,121	141,426
Bank deposits		14,661,996	12,702,746
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		162,808	192,697
Debentures to Stifel Financial Capital Trusts		$ 49,747	$ 64,962

[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 $695.6 million and $509.4 million at December 31, 2018 and 2017, respectively.

[2] Held-to-maturity securities are carried in the consolidated statements of financial condition at amortized cost, and the changes in the value of these securities, other than impairment charges, are not reported on the consolidated financial statements.

[3] 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 $558.6 million and $241.4 million at December 31, 2018 and 2017, respectively.