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           ACQUISITIONS AND DISPOSITIONS (Narrative) (Details) (USD $) 
         | 
        3 Months Ended | ||
|---|---|---|---|
| 
           Mar. 31, 2015
 
          helicopter 
         | 
        
           Mar. 31, 2014 
         | 
        
           Dec. 31, 2014 
         | 
      |
| Property, Plant and Equipment [Line Items] | |||
| Capital expenditures | $ 8,866,000us-gaap_PaymentsToAcquirePropertyPlantAndEquipment | $ 18,751,000us-gaap_PaymentsToAcquirePropertyPlantAndEquipment | |
| Capitalized interest payments | 1,700,000us-gaap_InterestCostsCapitalized | 1,000,000us-gaap_InterestCostsCapitalized | |
| Number of acquisitions | 0era_SignificantAcquisitionsAndDisposalsNumberOfAcquisitions | ||
| Proceeds from disposition of property and equipment | 5,379,000us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment | 3,566,000us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment | |
| Gains on asset dispositions, net | 3,388,000us-gaap_GainLossOnDispositionOfAssets | 2,891,000us-gaap_GainLossOnDispositionOfAssets | |
| AW139 Medium Helicopter [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Number of acquisitions | 
2era_SignificantAcquisitionsAndDisposalsNumberOfAcquisitions / us-gaap_PropertyPlantAndEquipmentByTypeAxis = era_Aw139MediumHelicopterMember  | 
        ||
| Helicopter [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Gains on asset dispositions, net | 
2,200,000us-gaap_GainLossOnDispositionOfAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = era_HelicopterMember  | 
        ||
| Construction in Progress [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Interest capitalized in property and equipment | 
6,700,000us-gaap_AccumulatedCapitalizedInterestCosts / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_ConstructionInProgressMember  | 
        
5,000,000us-gaap_AccumulatedCapitalizedInterestCosts / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_ConstructionInProgressMember  | 
      |
| Equipment Leased to Other Party [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Gains on asset dispositions, net | 
1,200,000us-gaap_GainLossOnDispositionOfAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_EquipmentLeasedToOtherPartyMember  | 
        ||
| Investment in lease asset | 
$ 2,300,000us-gaap_CapitalLeasesNetInvestmentInDirectFinancingAndSalesTypeLeases / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_EquipmentLeasedToOtherPartyMember  | 
        ||
| Number of disposals from purchase option exercised | 
3era_PropertyPlantandEquipmentNumberofDisposalsPurchaseOptionExercised / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_EquipmentLeasedToOtherPartyMember  | 
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- Definition 
          Property, Plant and Equipment, Number of Disposals, Purchase Option Exercised No definition available. 
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- Definition 
          Significant Acquisitions and Disposals, Number of Acquisitions No definition available. 
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- Definition 
          Amount of accumulated interest costs capitalized as part of property, plant and equipment cost basis. No definition available. 
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- Definition 
          The lessor's asset under sales type and direct financing leases. The net investment in direct financing and sales-type leases as of the balance sheet date consisting of: (a) minimum lease payments due on direct financing leases, (b) unguaranteed residual value, and (c) any unamortized initial direct costs on direct financing leases; less: (i) estimated executory costs, (ii) unearned income, and (iii) the accumulated allowance for uncollectible minimum lease payments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of interest capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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