Investments (Fixed Maturities Securities Proceeds) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Proceeds from maturities/prepayments	$ 1,736,809	$ 1,688,079	$ 1,251,269
Fixed maturities | Available-for-sale
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales	460,596	1,117,293	790,331
Proceeds from maturities/prepayments	1,218,844	624,640	465,347
Gross investment gains from sales and maturities	11,482	5,647	14,972
Gross investment losses from sales and maturities	(43,078)	(58,432)	(16,674)
Write-downs recognized in earnings	(2,358)	(20,600)	(2)
(Addition to) release of allowance for credit losses	2,761	(620)	(1,810)
Noncash or Part Noncash Divestiture, Amount of Consideration Received	$ 57,400	$ (53,900)	$ (4,400)