Revenue Recognition (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Stock borrow / stock loan	$ 4,045,000	$ 1,607,000
Gross revenue from stock borrow/ Stock loan	10,068,000	10,137,000
Expenses from stock borrow/stock loan	6,023,000	8,530,000
Client expenses	693,000	48,000
Other receivables	4,000	31,000
Accounts payable and accrued liabilities	$ 230,000	$ 158,000