Receivables From, Payables To, and Deposits With Broker-Dealers and Clearing Organizations (Schedule of Receivable) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Receivables from and deposits with broker-dealers and clearing organizations
DTCC / OCC / NSCC	$ 17,841,000	$ 3,059,000
Goldman Sachs	2,430,000	2,841,000
Pershing Capital	1,266,000	1,192,000
NFS	1,061,000	1,328,000
Securities fail-to-deliver	379,000	43,000
Globalshares	46,000	2,000
ICBC		10,000
Total Receivables from and deposits with broker-dealers and clearing organizations	23,023,000	8,475,000
Payables to broker-dealers and clearing organizations
Securities fail-to-receive	1,810,000	523,000
Total Payables to broker-dealers and clearing organizations	$ 1,810,000	$ 523,000