Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Accounting Policy (Narrative) (Details)

v2.4.1.9
Basis of Presentation and Accounting Policy (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
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