Percentage of economic interest retained by acquiree's management in the form of deferred consideration

No definition available.

Name:	gwr_Percentageofeconomicinterestretainedbyacquireesmanagement
Namespace Prefix:	gwr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of liability recognized arising from contingent consideration in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=gwr_FreightlinerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=gwr_HeartofGeorgiaRailroadMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value of Financial Instruments Financial instruments Carried at Fair Value-Level 3 (Details) £ in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2015	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 GBP (£)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 GBP (£)	Dec. 31, 2016 USD ($)
Freightliner [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Percentage of economic interest retained by acquiree's management			6.00%
Loss recognized in earnings as a result of the change in estimated fair value	$ 800	$ 1,000		$ 1,500	$ 1,100
Fair Value, Inputs, Level 3 [Member] \| Freightliner [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration, Liability						£ 27,110	$ 35,263	£ 25,882	$ 31,933
Fair Value, Inputs, Level 3 [Member] \| Heart of Georgia Railroad [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration, Liability							$ 5,676		$ 0