Fair Value Of Financial Instruments (Estimated Fair Values Of Financial Instruments Not Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities purchased under agreements to resell	[1]	$ 568,034	$ 699,900
Held-to-maturity securities	[2]	4,056,845	4,122,907
Securities sold under agreements to repurchase	[3]	466,284	535,394
Bank deposits		15,049,877	15,863,613
Borrowings		398,970	180,655
Senior notes		1,016,116	1,015,973
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		757,090	1,916,841
Cash segregated for regulatory purposes		73,684	132,814
Securities purchased under agreements to resell		568,034	699,900
Held-to-maturity securities		4,056,845	4,122,907
Bank loans		8,782,968	8,565,347
Loans held for sale		144,216	205,557
Securities sold under agreements to repurchase		466,284	535,394
Bank deposits		14,065,660	14,661,996
Federal Home Loan Bank advances		250,000	540,000
Borrowings		398,970	180,655
Senior notes		1,034,487	989,790
Debentures to Stifel Financial Capital Trusts		47,513	49,747
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash		757,090	1,916,841
Cash segregated for regulatory purposes		73,684	132,814
Securities purchased under agreements to resell		552,229	645,632
Securities sold under agreements to repurchase		51,978	87,273
Federal Home Loan Bank advances		250,000	540,000
Borrowings		398,970	180,655
Senior notes		1,034,487	989,790
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		15,805	54,268
Held-to-maturity securities		3,895,569	3,960,099
Bank loans		8,782,968	8,565,347
Loans held for sale		144,216	205,557
Securities sold under agreements to repurchase		414,306	448,121
Bank deposits		14,065,660	14,661,996
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		161,276	162,808
Debentures to Stifel Financial Capital Trusts		$ 47,513	$ 49,747

[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 $568.1 million and $695.6 million at March 31, 2019 and December 31, 2018, 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 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 $495.0 million and $558.6 million at March 31, 2019 and December 31, 2018, respectively.