Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 330,521		$ 551,248
Gains (losses) recognized from sale of loans	13,900	$ 2,500
Accrued interest receivable	21,300
Provision for credit losses	(3,427)	$ 18,978
Impaired loans more than 90 days past due	13,600		13,800
Troubled debt restructurings	200		200
Specific allowance	$ 8,200		$ 8,200
Collateralized loan portfolio	98.90%		98.80%
Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 330,500		$ 551,200
Unfunded Commitment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	1,800
Stifel Bancorp [Member] | Executive Officers and Directors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	25,100		23,600
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 25,100		$ 23,600