Fair Value of Derivative and Other Financial Instruments - Investments in NDT and Gross Realized Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Equity securities:
Net gains (losses) from equity securities sold	$ 4,209	$ (189)	$ 20,352	$ 1,758
Net gains (losses) from equity securities still held	9,358	(4,946)	4,273	3,673
Total net gains on equity securities	13,567	(5,135)	24,625	5,431
Available-for-sale debt securities:
Net gains (losses) on debt securities	203	(3,269)	7,701	(3,616)
Net gains (losses) on investment securities	$ 13,770	$ (8,404)	$ 32,326	$ 1,815

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Amount of unrealized and realized gain (loss) on investment in debt and equity securities.

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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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