Segment Reporting - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reconciliation of the totals reported for the reportable segments to the applicable line items in the consolidated financial statements
Combined gross profit	$ 134,974		$ 150,094	$ 428,565	$ 425,483
Operating costs and expenses
Selling, general and administrative expenses	42,127		40,134	121,447	111,600
Operating expenses	83,776		70,338	234,043	208,720
Gain on trustee taxes		$ (52,627)		(52,627)
Lease exit and termination gain	(3,506)			(3,506)
Amortization expense	3,079		2,260	7,984	6,781
Net loss (gain) on sale and disposition of assets	940		2,190	5,840	(7,291)
Goodwill and long-lived asset impairment	414		809	414	809
Total operating costs and expenses	126,830		115,731	313,595	320,619
Operating income	8,144		34,363	114,970	104,864
Interest expense	(22,579)		(20,626)	(65,637)	(65,836)
Income tax (expense) benefit	(29)		723	900	(72)
Net (loss) income	(14,464)		14,460	50,233	38,956
Net loss attributable to noncontrolling interest	384		418	1,142	1,242
Net (loss) income attributable to Global Partners LP	(14,080)		14,878	51,375	40,198
Unallocated
Operating costs and expenses
Selling, general and administrative expenses	42,127		40,134	121,447	111,600
Operating expenses	83,776		70,338	234,043	208,720
Gain on trustee taxes				(52,627)
Lease exit and termination gain	(3,506)			(3,506)
Amortization expense	3,079		2,260	7,984	6,781
Net loss (gain) on sale and disposition of assets	940		2,190	5,840	(7,291)
Goodwill and long-lived asset impairment	414		809	414	809
Total operating costs and expenses	$ 126,830		$ 115,731	$ 313,595	$ 320,619