Accounts Receivable Grants from Outside Parties (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
GRANTS FROM OUTSIDE PARTIES: [Abstract]
Grant proceeds received from outside parties	$ 16.4	$ 12.8
Amortization of deferred grants	$ 2.8gwr_AmortizationOfDeferredGrants	$ 2.7gwr_AmortizationOfDeferredGrants

Non-cash offset to depreciation expense from the amortization of grants from outside parties

No definition available.

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