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Reconciliation of Beginning and Ending Balances of Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs Level Three (Detail) - Marketable Securities - Debt and Equity Securities - Available-for-sale Securities $ in Thousands | 12 Months Ended
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Dec. 31, 2020 USD ($)
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |
Purchase | $ 10,000
Balance at end of year | 10,000
Unrealized Gain (Loss) on Security |
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |
Total gains or (losses) (realized/unrealized), included in other comprehensive income | (351)
Foreign Currency Items |
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |
Total gains or (losses) (realized/unrealized), included in other comprehensive income | $ 351

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