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Investments in Marketable Securities - Additional Information (Detail) (USD $)
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12 Months Ended |
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Dec. 31, 2014
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| Investments, Debt and Equity Securities [Abstract] | |
| Available-for-sale-securities, Continuous unrealized loss position for less than 12 months | $ 5,400,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss |
| Available-for-sale-securities, Continuous unrealized loss position for 12 months or longer | 0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss |
| Available for sale securities sold | 0us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt |
| Other-than-temporary impairment | $ 0us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities |
| Weighted average maturity period of available-for-sale securities | 9 years 7 months 6 days |
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- Definition
Available For Sale Securities Weighted Average Maturity No definition available.
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- Definition
Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The cash inflow associated with the sale of debt securities classified as available-for-sale securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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