Investments (Narrative) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2024 USD ($) securities	Dec. 31, 2023 USD ($) securities
Investments, Debt and Equity Securities [Abstract]
Available-for-sale fixed maturity securities in unrealized loss position, number of positions \| securities	1,485	1,386
Available-for-sale fixed maturity securities in unrealized loss position, number of positions, 12 months or longer \| securities	966	1,131
Available-for-sale fixed maturity securities, estimated fair value	$ 12,570,401	$ 9,982,329
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	743,003	661,282
Available-for-sale fixed maturity securities, estimated fair value, 12 months or longer	7,448,033	8,515,061
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 633,124	$ 650,461
Estimated average duration of fixed maturities	3 years 10 months 24 days
Percentage threshold of shareholders' equity used to define concentration of investments	10.00%	10.00%

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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