Variable Interest Entities Variable Interest Entity - Change in Fair Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fixed income securities, amortized cost	$ 289,712				$ 341,685				$ 289,712	$ 341,685
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	260				643				260	643
Realized Investment Gains (Losses)	(4,455)	$ (577)	$ 4,535	$ 0	1	$ 0	$ (20)	$ 38	(497)	19	$ (62)
Assets	8,058,378				8,428,320				8,058,378	8,428,320	$ 7,972,730
Liabilities	$ 6,862,857				$ 6,996,627				$ 6,862,857	$ 6,996,627