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           Income Taxes - Deferred tax assets and liabilities (Detail 2) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Dec. 31, 2014 
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           Dec. 31, 2013 
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|---|---|---|
| Deferred tax assets: | ||
| Loss carryforwards | $ 77,031us-gaap_DeferredTaxAssetsOperatingLossCarryforwards | $ 28,351us-gaap_DeferredTaxAssetsOperatingLossCarryforwards | 
| Shares in foreign subsidiary | 17,808us-gaap_DeferredTaxAssetsInvestmentInSubsidiaries | 59,587us-gaap_DeferredTaxAssetsInvestmentInSubsidiaries | 
| Other | 1,121us-gaap_DeferredTaxAssetsOther | 2,920us-gaap_DeferredTaxAssetsOther | 
| Valuation allowance | (81,704)us-gaap_DeferredTaxAssetsValuationAllowance | (84,695)us-gaap_DeferredTaxAssetsValuationAllowance | 
| Total net deferred assets | 14,256us-gaap_DeferredTaxAssetsNet | 6,163us-gaap_DeferredTaxAssetsNet | 
| Deferred tax liabilities: | ||
| Property and equipment | (20,888)us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment | (6,367)us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment | 
| Total deferred tax liabilities | (20,888)us-gaap_DeferredTaxLiabilities | (6,367)us-gaap_DeferredTaxLiabilities | 
| Net deferred tax liability | $ (6,632)us-gaap_DeferredTaxAssetsLiabilitiesNet | $ (204)us-gaap_DeferredTaxAssetsLiabilitiesNet | 
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- Definition 
          Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from the entity's investment in its wholly-owned subsidiaries. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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