Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 389,693	$ 205,557
Gains (losses) recognized from sale of loans	13,100	8,200	$ 12,300
Impaired loans more than 90 days past due	14,600	24,400
Troubled debt restructurings	200	9,100
Specific allowance	$ 8,182	$ 8,703
Collateralized loan portfolio	98.30%	98.40%
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	$ 3,100,000	$ 3,100,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	2,700,000	2,700,000
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	389,700	205,600
Stifel Bancorp [Member] | Executive Officers and Directors [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	24,500	28,800
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 24,500	$ 28,800