Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 465,739		$ 465,739		$ 423,999
Accrued interest receivable	$ 100,900		$ 100,900		$ 94,000
Collateralized loan portfolio	96.80%		96.80%		97.00%
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 465,700		$ 465,700		$ 424,000
Federal Reserve Discount Window [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	2,300,000		2,300,000
Residential Real Estate [Member] | Asset Pledged as Collateral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	7,800,000		7,800,000		7,400,000
Other Income [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gains (losses) recognized from sale of loans	(100)	$ (200)	(3,000)	$ (2,800)
Accounting Standards Update 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	9,200	13,400	20,600	24,900
Credit Loss Reserves Net	5,300	10,000	13,500	22,700
Accounting Standards Update 2016-13 [Member] | Unfunded Commitment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowances for unfunded credit commitments	3,900		7,400
Allowance For Unfunded Credit Commitment		$ 3,400		$ 2,200
Accounting Standards Update 2016-13 [Member] | Employee Retention Awards [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Loss Reserves Net			300
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 41,800		$ 41,800		$ 46,000