Annual report pursuant to Section 13 and 15(d)

Fair Value Hierarchy Financial Instruments Measured at Fair Value on Recurring Basis (Detail)

v2.4.1.9
Fair Value Hierarchy Financial Instruments Measured at Fair Value on Recurring Basis (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Long-Term Investments, at fair value $ 4,160us-gaap_EquityMethodInvestmentsFairValueDisclosure
Trading Securities 20,002us-gaap_TradingSecurities
Total 24,162us-gaap_MarketableSecurities
US Treasury Securities [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 19,998us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_USTreasurySecuritiesMember
Money Market Funds [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 4us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_MoneyMarketFundsMember
Fair Value, Inputs, Level 1 [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Long-Term Investments, at fair value 0us-gaap_EquityMethodInvestmentsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Trading Securities 20,002us-gaap_TradingSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Total 20,002us-gaap_MarketableSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 19,998us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_USTreasurySecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 4us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_MoneyMarketFundsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Fair Value, Inputs, Level 2 [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Long-Term Investments, at fair value 0us-gaap_EquityMethodInvestmentsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Trading Securities 0us-gaap_TradingSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Total 0us-gaap_MarketableSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 0us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_USTreasurySecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 0us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_MoneyMarketFundsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Fair Value, Inputs, Level 3 [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Long-Term Investments, at fair value 4,160us-gaap_EquityMethodInvestmentsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Trading Securities 0us-gaap_TradingSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Total 4,160us-gaap_MarketableSecurities
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities 0us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_USTreasurySecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Trading Securities $ 0us-gaap_TradingSecurities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_MoneyMarketFundsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member