Investments - Gains and Proceeds (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments
Net realized gains on sale of investments		$ 100
Proceeds from sale of available-for-sale debt securities	$ 1,200	1,200
Maturities of investments - debt securities	117,000	11,000	$ 7,000
Purchases of available-for-sale securities	157,900	$ 58,900
Maximum
Investments
Net realized gains on sale of investments	$ 100

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).

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Amount of cash inflow from maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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