Investment Securities - Investments in Debt and Equity Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2024	Dec. 31, 2023
Cost
Equity	$ 354,561	$ 344,669
Debt	840,701	908,316
Other	14,734	2,889
Total	1,209,996	1,255,874
Gains
Equity	279,893	246,795
Debt	2,621	3,938
Other	113	61
Total	282,627	250,794
Losses
Equity	(6,177)	(5,549)
Debt	(22,189)	(25,181)
Other	(97)	(36)
Total	(28,463)	(30,766)
Fair Value
Equity	628,277	585,915
Debt	821,133	887,073
Other	14,750	2,914
Total	$ 1,464,160	$ 1,475,902

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