Fair Value Of Financial Instruments (Schedule Of Fair Value Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Cash and cash equivalents	$ 171,890	$ 72,596
Securities purchased under agreements to resell	156,341	158,695
Trading securities owned	923,452	763,608
Available-for-sale Securities	1,729,837	1,625,168
Investments	268,082	236,434
Securities purchased under agreements to repurchase	108,529	140,346
Bank deposits	3,556,568	3,346,133
Trading securities sold, but not yet purchased	588,922	319,742
Derivative contracts	17,459	19,934
Carrying Value [Member]
Cash and cash equivalents	573,664	403,941
Restricted cash	4,415	4,414
Cash segregated for regulatory purposes	32	128,031
Securities purchased under agreements to resell	156,341	158,695
Trading securities owned	923,452	763,608
Available-for-sale Securities	1,729,837	1,625,168
Held-to-maturity securities	716,273	708,008
Loans held for sale	165,698	214,531
Bank loans	886,647	815,937
Investments	268,082	236,434
Securities purchased under agreements to repurchase	108,529	140,346
Bank deposits	3,556,568	3,346,133
Trading securities sold, but not yet purchased	588,922	319,742
Securities sold, but not yet purchased	24,550	22,966
Derivative contracts	17,459	19,934
Senior notes	325,000	325,000
Non-Recourse Debt	55,934	58,992
Debentures to Stifel Financial Capital Trusts	82,500	82,500
Liabilities subordinated to the claims of general creditors	3,131	5,318
Estimated Fair Value [Member]
Cash and cash equivalents	573,664	403,941
Restricted cash	4,415	4,414
Cash segregated for regulatory purposes	32	128,031
Securities purchased under agreements to resell	156,341	158,695
Trading securities owned	923,452	763,608
Available-for-sale Securities	1,729,837	1,625,168
Held-to-maturity securities	725,843	715,274
Loans held for sale	165,698	214,531
Bank loans	909,115	834,188
Investments	268,082	236,434
Securities purchased under agreements to repurchase	108,529	140,346
Bank deposits	3,581,155	3,368,643
Trading securities sold, but not yet purchased	588,922	319,742
Securities sold, but not yet purchased	24,550	22,966
Derivative contracts	17,459	19,934
Senior notes	349,242	338,475
Non-Recourse Debt	57,069	58,992
Debentures to Stifel Financial Capital Trusts	68,113	66,545
Liabilities subordinated to the claims of general creditors	$ 3,048	$ 5,204