Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income applicable to Stifel Financial Corp.	$ 120,527	$ 109,414	$ 315,003	$ 317,706
Preferred dividends	9,897	4,844	19,584	12,476
Net income available to common shareholders	$ 110,630	$ 104,570	$ 295,419	$ 305,230
Average shares used in basic computation	70,627	71,197	70,814	72,512
Dilutive effect of stock options and units	5,223	6,947	4,898	6,314
Average shares used in diluted computation	75,850	78,144	75,712	78,826
Basic	$ 1.57	$ 1.47	$ 4.17	$ 4.21
Diluted	$ 1.46	$ 1.34	$ 3.90	$ 3.87