Revenue Recognition (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Stock borrow / stock loan	$ 3,578,000	$ 1,847,000
Gross revenue from stock borrow/ Stock loan	7,465,000	4,830,000
Expenses from stock borrow/stock loan	$ 3,887,000	$ 2,983,000