Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income applicable to Stifel Financial Corp.	$ 107,887	$ 109,085	$ 194,476	$ 208,292
Preferred dividends	4,843	5,288	9,687	7,632
Net income available to common shareholders	$ 103,044	$ 103,797	$ 184,789	$ 200,660
Average shares used in basic computation	70,527	72,519	70,905	73,180
Dilutive effect of stock options and units	3,860	6,560	4,746	5,980
Average shares used in diluted computation	74,387	79,079	75,651	79,160
Basic	$ 1.46	$ 1.43	$ 2.61	$ 2.74
Diluted	$ 1.39	$ 1.31	$ 2.44	$ 2.53