The amount of unscheduled payments on debt applied to principal.

No definition available.

Name:	gwr_DebtInstrumentPrepaymentPrincipal
Namespace Prefix:	gwr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ 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=gwr_CreditagreementMember
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:	gwr_QuarterlyPaymentPeriodAxis=gwr_Period3Member
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_Period1Member
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	gwr_QuarterlyPaymentPeriodAxis=gwr_Period2Member
Namespace Prefix:
Data Type:	na
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Long-Term Debt Amortization of Term Loans (Details) - Credit agreement [Member] £ in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017 GBP (£)	Jun. 30, 2017 GBP (£)	Jun. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)
United States Term Loan [Member]
Prepayments of debt			$ 99,800
Principal amount of each quarterly installment			5,200
Long-term Debt, Gross				$ 1,323,000
Debt Instrument, Interest Rate, Stated Percentage	2.98%	2.98%		2.98%
United States Term Loan [Member] \| Period 3 [Member]
Principal payment upon maturity				$ 1,300,000
U.K. term loan [Member]
Principal amount of each quarterly installment		£ 3,200	$ 2,500
Long-term Debt, Gross	£ 95,868	£ 95,868		$ 124,696
Debt Instrument, Interest Rate, Stated Percentage	2.00%	2.00%		2.00%
U.K. term loan [Member] \| Period 1 [Member]
Principal amount of each quarterly installment \| £	£ 1,271
U.K. term loan [Member] \| Period 2 [Member]
Principal amount of each quarterly installment \| £	2,542
U.K. term loan [Member] \| Period 3 [Member]
Principal payment upon maturity \| £	£ 75,532	£ 75,532