Prepaid Service Contract (Details) - USD ($)		1 Months Ended
	Apr. 21, 2020	Apr. 21, 2020	Sep. 30, 2020	Dec. 31, 2019	[1]
Capitalized Contract Cost [Line Items]
Prepaid asset - non-current			$ 1,890,000
InvestCloud, Inc [Member] | Restricted Stock [Member]
Capitalized Contract Cost [Line Items]
Restricted common stock issued to InvestCloud		193,906
Per share price	$ 5.81	$ 5.81
License Fee [Member] | InvestCloud, Inc [Member]
Capitalized Contract Cost [Line Items]
Initial term of license		3 years
Annual license fee		$ 600,000
Amortization period of prepaid licensing fees	3 months
Upfront Professional Service Fee [Member] | InvestCloud, Inc [Member]
Capitalized Contract Cost [Line Items]
Consideration paid		1,000,000
Professional Services [Member] | InvestCloud, Inc [Member]
Capitalized Contract Cost [Line Items]
Value of restricted common stock issued to InvestCloud	$ 1,100,000
Prepaid asset - non-current	$ 2,100,000	$ 2,100,000
Amortization period of professional services prepaid assets	3 years

[1] Statement of financial condition as of December 31, 2019 represents the pro forma combination of Siebert and StockCross balances. See "Note 3 - Acquisitions" for additional detail.