Segment Reporting - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the totals reported for the reportable segments to the applicable line items in the consolidated financial statements
Combined gross profit	$ 151,001	$ 187,769	$ 167,143	$ 156,844	$ 221,844	$ 134,974	$ 149,261	$ 144,330		$ 662,757	$ 650,409	$ 583,052
Operating costs and expenses
Selling, general and administrative expenses										170,937	171,002	155,033
Operating expenses										342,382	321,115	283,650
Loss on trustee taxes								(52,600)	$ 16,200		(52,627)	16,194
Lease exit gain (loss)											3,506
Lease exit and termination gain, ASC842						(3,500)				(493)		16,194
Amortization expense										11,431	10,960	9,206
Net (gain) loss on sale and disposition of assets	(2,400)	300	(1,100)	500	100	900	3,000	1,900		(2,730)	5,880	(1,624)
Goodwill and long-lived asset impairment	1,400	600								2,022	414	809
Total costs and operating expenses										523,549	453,238	463,268
Operating income	20,682	50,877	37,875	29,774	82,201	8,144	27,619	79,207		139,208	197,171	119,784
Interest expense										(89,856)	(89,145)	(86,230)
Loss on early extinguishment of debt		(13,100)								(13,080)
Income tax (expense) benefit										(1,094)	(5,623)	23,563
Net income	(880)	14,893	14,371	6,794	52,170	(14,464)	6,022	58,675		35,178	102,403	57,117
Net loss attributable to noncontrolling interest										689	1,502	1,635
Net income attributable to Global Partners LP	$ (828)	$ 15,080	$ 14,489	$ 7,126	$ 52,530	$ (14,080)	$ 6,413	$ 59,042		35,867	103,905	58,752
Unallocated
Operating costs and expenses
Selling, general and administrative expenses										170,937	171,002	155,033
Operating expenses										342,382	321,115	283,650
Loss on trustee taxes											(52,627)	16,194
Lease exit gain (loss)											(3,506)
Lease exit and termination gain, ASC842										(493)
Amortization expense										11,431	10,960	9,206
Net (gain) loss on sale and disposition of assets										(2,730)	5,880	(1,624)
Goodwill and long-lived asset impairment										2,022	414	809
Total costs and operating expenses										$ 523,549	$ 453,238	$ 463,268