Recently Issued Accounting Standards Accounting Standards Not Yet Effective (Details) (Accounting Standards Update 2015-03 [Member], Scenario, Forecast [Member])	3 Months Ended
Mar. 31, 2016
Impact on total assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption	1.00%
Impact on total debt [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption	1.00%

Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements.

No definition available.

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