Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 225,365		$ 156,912
Gains (losses) recognized from sale of loans	600	$ 700
Accrued interest receivable	82,600		65,700
Provision for credit losses	5,376	4,854
Impaired loans more than 90 days past due	10,700		10,300
Troubled debt restructurings	100		200
Specific allowance	$ 6,600		$ 6,500
Collateralized loan portfolio	97.20%		97.50%
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 225,400		$ 156,900
Unfunded Commitment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	500	3,400
Residential Real Estate [Member] | Asset Pledged as Collateral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	7,400,000		7,000,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	(1,331)	$ (254)
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 85,500		$ 86,400