Revenue Recognition (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Stock borrow / stock loan	$ 444,000	$ 581,000
Gross revenue from stock borrow/ Stock loan	1,663,000	3,439,000
Expenses from stock borrow/stock loan	1,219,000	$ 2,858,000
Client expenses	218,000
Other receivables	16,000
Accounts payable and accrued liabilities	$ 186,000