Description of the frequency of periodic payments (monthly, quarterly, annual).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentFrequencyOfPeriodicPayment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LoansPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	gwr_QuarterlyPaymentPeriodAxis=gwr_Period1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwr_UnitedStatesTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwr_AustralianTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwr_UnitedKingdomTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	gwr_QuarterlyPaymentPeriodAxis=gwr_Period2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	gwr_QuarterlyPaymentPeriodAxis=gwr_Period3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-term Debt Amortization of Term Loans (Details) - 12 months ended Dec. 31, 2015 - Loans Payable [Member] £ in Thousands, AUD in Thousands, $ in Thousands	AUD	GBP (£)	USD ($)	GBP (£)	USD ($)
Debt Instrument, Frequency of Periodic Payment	quarterly	quarterly	quarterly
September 30, 2016 through June 30, 2018 [Member] \| United States dollar term loan [Member]
Debt Instrument, Periodic Payment, Principal \| $			$ 22,275
September 30, 2016 through June 30, 2018 [Member] \| Australian dollar term loan [Member]
Debt Instrument, Periodic Payment, Principal \| AUD	AUD 4,058
September 30, 2016 through June 30, 2018 [Member] \| British pound term loan [Member]
Debt Instrument, Periodic Payment, Principal \| £		£ 1,271
September 30, 2018 through December 31, 2019 [Member] \| United States dollar term loan [Member]
Debt Instrument, Periodic Payment, Principal \| $			$ 44,550
September 30, 2018 through December 31, 2019 [Member] \| Australian dollar term loan [Member]
Debt Instrument, Periodic Payment, Principal \| AUD	8,116
September 30, 2018 through December 31, 2019 [Member] \| British pound term loan [Member]
Debt Instrument, Periodic Payment, Principal \| £		£ 2,542
Maturity date - March 31, 2020 [Member] \| United States dollar term loan [Member]
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid \| $					$ 1,326,500
Maturity date - March 31, 2020 [Member] \| Australian dollar term loan [Member]
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid \| AUD	AUD 208,470
Maturity date - March 31, 2020 [Member] \| British pound term loan [Member]
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid \| £				£ 76,261