Investments in Marketable Securities - Gross Realized Gains and Losses from Sale of Available for Sale Securities (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
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| Investments, Debt and Equity Securities [Abstract] | ||||
| Gross realized gains | $ 0 | $ 1 | $ 12 | $ 2 |
| Gross realized losses | $ 0 | $ 0 | $ 0 | $ 0 |
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- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. No definition available.
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| X | ||||||||||
- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. No definition available.
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| X | ||||||||||
- References No definition available.
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