Annual report pursuant to Section 13 and 15(d)

SEGMENT INFORMATION, MAJOR CUSTOMERS AND GEOGRAPHICAL DATA Narrative (Details)

v2.4.1.9
SEGMENT INFORMATION, MAJOR CUSTOMERS AND GEOGRAPHICAL DATA Narrative (Details) (Sales [Member])
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Foreign Operations [Member]
      
Revenue, Major Customer [Line Items]      
Concentration Risk, Percentage 15.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_StatementGeographicalAxis
= era_ForeignOperationsMember 		18.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_StatementGeographicalAxis
= era_ForeignOperationsMember 		22.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_StatementGeographicalAxis
= era_ForeignOperationsMember
Anadarko Petroleum Corporation [Member]
      
Revenue, Major Customer [Line Items]      
Concentration Risk, Percentage 26.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_MajorCustomersAxis
= era_AnadarkoPetroleumCorporationMember 		19.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_MajorCustomersAxis
= era_AnadarkoPetroleumCorporationMember 		15.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_MajorCustomersAxis
= era_AnadarkoPetroleumCorporationMember
U.S. Government [Member]
      
Revenue, Major Customer [Line Items]      
Concentration Risk, Percentage 10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_MajorCustomersAxis
= era_UnitedStatesGovernmentMember 		11.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_MajorCustomersAxis
= era_UnitedStatesGovernmentMember 		11.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesMember
/ us-gaap_MajorCustomersAxis
= era_UnitedStatesGovernmentMember