Annual report pursuant to Section 13 and 15(d)

LONG-TERM DEBT - Narrative (Details)

v2.4.1.9
LONG-TERM DEBT - Narrative (Details) (USD $)
 12 Months Ended 0 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 07, 2012
Nov. 24, 2010
Dec. 23, 2010
Mar. 31, 2014
Debt Instrument [Line Items]              
Long-term Debt $ 312,426,000us-gaap_LongTermDebt $ 285,311,000us-gaap_LongTermDebt          
Payments of Debt Issuance Costs 2,446,000us-gaap_PaymentsOfDebtIssuanceCosts 0us-gaap_PaymentsOfDebtIssuanceCosts 4,754,000us-gaap_PaymentsOfDebtIssuanceCosts        
Proceeds from issuance of long-term debt 0us-gaap_ProceedsFromIssuanceOfLongTermDebt 0us-gaap_ProceedsFromIssuanceOfLongTermDebt 284,622,000us-gaap_ProceedsFromIssuanceOfLongTermDebt        
Senior Notes [Member]              
Debt Instrument [Line Items]              
Stated interest rate       7.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Senior Notes [Member] | 7.750% Senior Notes [Member]              
Debt Instrument [Line Items]              
Long-term Debt 200,000,000us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		200,000,000us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		  200,000,000us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Stated interest rate 7.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		7.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		  7.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Proceeds from issuance of long-term debt       191,900,000us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Face amount       200,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Secured Debt [Member]              
Debt Instrument [Line Items]              
Long-term Debt 27,426,000us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		30,311,000us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		         
Secured Debt [Member] | Promissory Note to Purchase Medium Helicopter [Member]              
Debt Instrument [Line Items]              
Face amount         11,700,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseMediumHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		   
Debt instrument, interest rate at year-end 2.83%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseMediumHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		           
Note required monthly payments 100,000us-gaap_DebtInstrumentPeriodicPayment
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseMediumHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		           
Note required final payment 5,900,000era_DebtInstrumentFinalPayment
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseMediumHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		           
Secured Debt [Member] | Promissory Note to Purchase Heavy Helicopter [Member]              
Debt Instrument [Line Items]              
Face amount           27,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseHeavyHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		 
Debt instrument, interest rate at year-end 2.85%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseHeavyHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		           
Note required monthly payments 200,000us-gaap_DebtInstrumentPeriodicPayment
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseHeavyHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		           
Note required final payment 19,000,000era_DebtInstrumentFinalPayment
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseHeavyHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		           
Prior to December 15, 2015 [Member] | Senior Notes [Member] | 7.750% Senior Notes [Member]              
Debt Instrument [Line Items]              
Debt instrument, redemption price, percentage of principal amount redeemed       35.00%era_DebtInstrumentRedemptionPricePercentageofPrincipalAmountRedeemed
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodOneMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Debt Instrument, Redemption Price, Percentage       107.75%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= era_Senior7Point750PercentNotesMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodOneMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		     
Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Line of credit facility, maximum borrowing capacity             300,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
Line of Credit Facility, Borrowing Capacity Increase Limit             100,000,000era_LineofCreditFacilityBorrowingCapacityIncreaseLimit
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.375%us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember 		           
Remaining borrowing capacity 214,300,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember 		           
Letters of credit outstanding 700,000us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember 		           
Revolving Credit Facility [Member] | Secured Debt [Member]              
Debt Instrument [Line Items]              
Long-term Debt 85,000,000us-gaap_LongTermDebt
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		55,000,000us-gaap_LongTermDebt
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		         
Repayments of borrowings outstanding       190,000,000us-gaap_RepaymentsOfLongTermDebt
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember 		     
Letter of Credit [Member]              
Debt Instrument [Line Items]              
Line of credit facility, maximum borrowing capacity             $ 50,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_LetterOfCreditMember
Base Rate [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate 1.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_VariableRateAxis
= us-gaap_BaseRateMember 		           
London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member] | Promissory Note to Purchase Medium Helicopter [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate         2.60%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseMediumHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember 		   
London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member] | Promissory Note to Purchase Heavy Helicopter [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate           2.60%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= era_PromissoryNotetoPurchaseHeavyHelicopterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember 		 
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate 2.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember 		           
Minimum [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.375%us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember 		           
Minimum [Member] | Base Rate [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate 0.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_BaseRateMember 		           
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate 1.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember 		           
Maximum [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.50%us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember 		           
Maximum [Member] | Base Rate [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate 2.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_VariableRateAxis
= us-gaap_BaseRateMember 		           
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Basis spread on variable rate 3.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_CreditFacilityAxis
= us-gaap_RevolvingCreditFacilityMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember