Annual report pursuant to Section 13 and 15(d)

NATURE OF OPERATIONS AND ACCOUNTING POLICIES Impairment of 50% or Less Owned Companies Narrative (Details)

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NATURE OF OPERATIONS AND ACCOUNTING POLICIES Impairment of 50% or Less Owned Companies Narrative (Details) (USD $)
12 Months Ended 0 Months Ended 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Mar. 02, 2012
Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]        
Recognized impairment charge $ 0us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment $ 0us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment    
Aeroleo [Member]        
Schedule of Equity Method Investments [Line Items]        
Recognized impairment charge     $ 5,900,000us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= era_AeroleoMember
$ 5,900,000us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= era_AeroleoMember