Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 224,017		$ 224,017		$ 156,912
Gains (losses) recognized from sale of loans	2,000	$ 100	2,600	$ 600
Accrued interest receivable	73,400		73,400		65,700
Provision for credit losses	6,117	3,318	11,493	8,172
Impaired loans more than 90 days past due	11,400		11,400		10,300
Troubled debt restructurings	100		100		200
Specific allowance	$ 6,300		$ 6,300		$ 6,500
Collateralized loan portfolio	97.20%		97.20%		97.50%
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 0		$ 0		$ 156,900
Unfunded Commitment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	1,700	$ 9,500	1,300	$ 12,900
Residential Real Estate [Member] | Asset Pledged as Collateral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	7,100,000		7,100,000		7,000,000
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 70,600		$ 70,600		$ 86,400