Marketable Securities - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2023
Net investment income
Gross investment income	$ 3,831	$ 12,231
Investment expenses	(65)	(203)
Net investment income (excluding net realized capital losses)	3,766	12,028
Net realized capital losses	0	(39)
Net investment income	$ 3,766	$ 11,989

Investment Income, Excluding Realized Gain (Loss)

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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 before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities.

+ References

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- Definition

Amount of expenses related to the generation of investment income.

+ References

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Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

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