Financial Instruments With Off-Balance Sheet Risk (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financial Instruments With Off-Balance Sheet Risk [Abstract]
Margin loans extended	$ 365.4	$ 581.8
Receivables from customers	$ 52.1	$ 84.2

Amount due from customers for fees and charges arising from transactions related to the entity's brokerage activities and operations.

No definition available.

Name:	sieb_ReceivablesFromCustomers1
Namespace Prefix:	sieb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant