Investments In Available-For-Sale Securities And Other Cost Investments - Unrealized Holding Gains and Losses (Details) - USD ($) |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Investments In Available-For-Sale Securities And Other Cost Investments | ||
| Gross unrealized holding gains | $ 0 | $ 0 |
| Gross unrealized holding losses | $ 0 | $ 0 |
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- Definition Investments in Available-for-Sale Securities and Other Cost Investments [Abstract] No definition available.
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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