Investments in Fixed Maturity Securities (HTM Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 53	$ 127	$ 114	$ 387
Cumulative effect adjustment resulting from changes in accounting principles	48	121	48	121
Provision for expected credit losses	(5)	(6)	(66)	(266)
Allowance for expected credit losses, end of period	$ 48	$ 121	$ 48	$ 121