Investment in Securities (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 32,800		$ 32,600
Available-for-sale securities Realizes Losses - Write offs	(9,700)	$ (5,700)
Catch-up premium amortization adjustment	(1,300)	$ (500)
Arlington Asset Investment Corp.
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 4,400		$ 1,100