Investments in Fixed Maturity Securities (HTM Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 43	$ 114
Cumulative effect adjustment resulting from changes in accounting principles	38	107
Provision for expected credit losses	(5)	(7)
Allowance for expected credit losses, end of period	$ 38	$ 107