Investments - Available For Sale Investments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation Of Debt Securities, Available-For-Sale [Roll Forward]
Available for sale investments at start of year	$ 1,729	$ 49,628
Purchases	480	0	$ 9,603
Sales and maturities	(497)	(47,902)	(21,686)
Realized gain on sale of short term investments	0	234
Unrealized capital (loss)/gain - investments	0	(231)	681
Available for sale investments at end of year	$ 1,712	$ 1,729	$ 49,628

Reconciliation Of Debt Securities, Available-For-Sale [Roll Forward]

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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), classified as current.

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The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

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Amount, after tax and before adjustment, of unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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Amount of cash outflow to acquire 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 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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