Income Taxes (Details)	3 Months Ended
Mar. 31, 2015 item
Income Taxes
Number of wholly owned subsidiaries which are taxable for federal and state income tax purposes	1

Represents the number of wholly owned subsidiaries of the entity which are taxable for federal and state income tax purposes.

No definition available.

Name:	glp_NumberOfWhollyOwnedSubsidiariesWhichAreTaxableForFederalAndStateIncomeTaxPurposes
Namespace Prefix:	glp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration