Recently Issued Accounting Standards Accounting Pronouncements (Details) - Scenario, Forecast [Member] - Accounting Standards Update 2015-03 [Member]	12 Months Ended
Dec. 31, 2016
Impact on total assets [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption	1.00%
Impact on total debt [Member] [Member]
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