Investment In Securities - Trading Securities, Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Credit Risk and Non-Agency Securities
Fair Value
Less than 12 months, fair value	$ 362	$ 1,860
12 months or more, fair value	0	0
Total, fair value	362	1,860
Unrealized Losses
Less than 12 months, unrealized loss	(3)	(13)
12 months or more, unrealized loss	0	0
Total, unrealized loss	$ (3)	(13)
U.S. Treasury Securities
Fair Value
Less than 12 months, fair value		98,646
12 months or more, fair value		0
Total, fair value		98,646
Unrealized Losses
Less than 12 months, unrealized loss		(57)
12 months or more, unrealized loss		0
Total, unrealized loss		$ (57)