Investment in Securities (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 38,900		$ 38,900		$ 35,100
Available-for-sale securities Realizes Losses - Write offs	(12,000)	$ (2,000)	(20,400)	$ (4,500)
Catch-up premium amortization adjustment	$ 300	$ 1,600	$ (600)	$ 3,100