Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 423,999	$ 156,912
Gains (losses) recognized from sale of loans			$ 29,800
Accrued interest receivable	94,000	65,700
Impaired loans more than 90 days past due	45,500	10,300
Troubled debt restructurings	100	200
Specific allowance	$ 5,000	$ 6,500
Collateralized loan portfolio	97.00%	97.50%
ASU 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Loss Reserves Net	$ 25,000	$ 33,500
Allowance for credit losses	25,600	16,500
Uncollectible broker notes	2,300
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
Other Income
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gains (losses) recognized from sale of loans	1,200	7,800
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	424,000	156,900
Unfunded Commitment [Member] | ASU 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reserve For Unfunded Commitments For Credit Loss	2,900	17,000
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 46,000	$ 86,400