Bank Loans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 21, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	$ 534,593		$ 423,999
Accrued interest receivable	96,800			$ 94,000
Provision for credit losses	4,558	$ 5,376
Impaired loans more than 90 days past due	59,400		45,500
Troubled debt restructurings	100		100
Specific allowance	$ 6,700		$ 5,000
Collateralized loan portfolio	96.90%		97.00%
ASU 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Loss Reserves Net	$ 5,300	4,900
Allowance for credit losses	4,600	5,400
ASU 2016-13 [Member] | Employee Retention Award
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Loss Reserves Net	300
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	534,600		$ 424,000
Unfunded Commitment [Member] | ASU 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reserve For Unfunded Commitments For Credit Loss	400	500
Residential Real Estate [Member] | Asset Pledged as Collateral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	7,500,000		7,400,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses	(697)	(1,331)
Other Income
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gains (losses) recognized from sale of loans	1,400	$ 600
Stifel Bancorp [Member] | Executive Officers and Directors of Certain Affiliated Entities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding amount	$ 42,300		$ 46,000