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           Basis of Presentation and Accounting Policy (Narrative) (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Mar. 31, 2015 
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           Dec. 31, 2014 
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           Mar. 31, 2014 
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           Dec. 31, 2013 
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|---|---|---|---|---|
| Nature of Operations and Accounting Policies [Line Items] | ||||
| Deferred revenue | $ 32,666us-gaap_DeferredRevenue | $ 31,047us-gaap_DeferredRevenue | $ 26,469us-gaap_DeferredRevenue | $ 24,243us-gaap_DeferredRevenue | 
| Aeroleo [Member] | ||||
| Nature of Operations and Accounting Policies [Line Items] | ||||
| Deferred revenue | 
$ 32,700us-gaap_DeferredRevenue / era_CustomerAxis = era_AeroleoMember  | 
        
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- Definition 
          Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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