Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 1,016,127		$ 578,980
Accrued interest receivable	$ 88,800		$ 92,600
Collateralized loan portfolio	96.80%		96.80%
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 1,000,000		$ 579,000
Federal Reserve Discount Window [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	2,500,000		2,500,000
Residential Real Estate [Member] | Asset Pledged as Collateral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	8,100,000		7,900,000
Other Income [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gains (losses) recognized from sale of loans	600		1,400
Accounting Standards Update 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	12,500	$ 4,600
Credit loss reserves net	12,000	5,300
Accounting Standards Update 2016-13 [Member] | Unfunded Commitment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowances for unfunded credit commitments	500	400
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	$ 50,400		$ 39,600