Revenue Recognition (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Stock borrow / stock loan	$ 3,465,000	$ 1,267,000	$ 7,552,000	$ 2,482,000
Gross revenue from stock borrow/ Stock loan	7,754,000	2,499,000	19,605,000	6,170,000
Expenses from stock borrow/stock loan	4,289,000	1,232,000	12,053,000	3,688,000
Client expenses	170,000	$ 142,000	500,000	$ 494,000
Other receivables	33,000		33,000
Accounts payable and accrued liabilities	$ 261,000		$ 261,000