Investment in Securities (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 32,600	$ 35,100
Available-for-sale securities Realizes Losses - Write offs	(31,700)	(6,000)	$ (3,300)
Catch-up premium amortization adjustment	(100)	$ 4,100	$ 1,300
Arlington Asset Investment Corp.
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 1,100