Condensed Consolidating Guarantor Financial Statements - Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Product	$ 236,896	$ 220,131
Service	64,073	61,877
Other	13,882	16,302
Revenue	314,851	298,310
Expenses:
Cost of products sold	196,947	192,072
Operating	50,192	53,090
General and administrative	21,060	32,310
Depreciation and amortization	24,047	23,734
Loss (gain) on disposal of long-lived assets, net	13,307	1,058
Total expenses	305,553	302,264
Earnings from equity method investments	23,071	20,559
Loss on issuance of common units by equity method investee	(41)	0
Operating income	32,328	16,605
Other expenses (income), net:
Interest expense	18,935	14,591
Foreign currency transaction loss (gain)	1,469	(519)
Loss (gain) on sale or impairment of equity method investment	39,764	(7,894)
Other income, net	(187)	(91)
Total other expenses, net	59,981	6,087
Income (loss) from continuing operations before income taxes	(27,653)	10,518
Income tax expense (benefit)	(21,407)	4,742
Income (loss) from continuing operations	(6,246)	5,776
Loss from discontinued operations, net of income taxes	(2)	0
Net income (loss)	(6,248)	5,776
Less: net income attributable to noncontrolling interests	9,020	4,310
Net income (loss) attributable to SemGroup	(15,268)	1,466
Other comprehensive loss, net of income taxes	(4,109)	(9,060)
Comprehensive income (loss)	(10,357)	(3,284)
Less: comprehensive income attributable to noncontrolling interests	9,020	4,310
Comprehensive income (loss) attributable to SemGroup	(19,377)	(7,594)
Parent Company [Member]
Revenues:
Product	0	0
Service	0	0
Other	0	0
Revenue	0	0
Expenses:
Cost of products sold	0	0
Operating	0	0
General and administrative	5,872	17,602
Depreciation and amortization	380	294
Loss (gain) on disposal of long-lived assets, net	0	0
Total expenses	6,252	17,896
Earnings from equity method investments	6,590	14,805
Loss on issuance of common units by equity method investee	(41)
Operating income	297	(3,091)
Other expenses (income), net:
Interest expense	(577)	1,422
Foreign currency transaction loss (gain)	0	0
Loss (gain) on sale or impairment of equity method investment	39,764	(7,894)
Other income, net	(237)	(792)
Total other expenses, net	38,950	(7,264)
Income (loss) from continuing operations before income taxes	(38,653)	4,173
Income tax expense (benefit)	(23,385)	2,707
Income (loss) from continuing operations	(15,268)
Loss from discontinued operations, net of income taxes	0
Net income (loss)	(15,268)	1,466
Less: net income attributable to noncontrolling interests	0	0
Net income (loss) attributable to SemGroup	(15,268)	1,466
Other comprehensive loss, net of income taxes	(20,466)	8,646
Comprehensive income (loss)	(35,734)	10,112
Less: comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to SemGroup	(35,734)	10,112
Guarantor Subsidiaries [Member]
Revenues:
Product	33,398	51,053
Service	12,868	14,459
Other	0	0
Revenue	46,266	65,512
Expenses:
Cost of products sold	24,609	40,668
Operating	7,693	8,114
General and administrative	2,246	2,064
Depreciation and amortization	8,874	7,033
Loss (gain) on disposal of long-lived assets, net	13,052	(1)
Total expenses	56,474	57,878
Earnings from equity method investments	19,180	12,528
Loss on issuance of common units by equity method investee	0
Operating income	8,972	20,162
Other expenses (income), net:
Interest expense	8,003	5,491
Foreign currency transaction loss (gain)	0	0
Loss (gain) on sale or impairment of equity method investment	0	0
Other income, net	0	0
Total other expenses, net	8,003	5,491
Income (loss) from continuing operations before income taxes	969	14,671
Income tax expense (benefit)	0	0
Income (loss) from continuing operations	969
Loss from discontinued operations, net of income taxes	(2)
Net income (loss)	967	14,671
Less: net income attributable to noncontrolling interests	0	0
Net income (loss) attributable to SemGroup	967	14,671
Other comprehensive loss, net of income taxes	216	0
Comprehensive income (loss)	1,183	14,671
Less: comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to SemGroup	1,183	14,671
Non-Guarantor Subsidiaries [Member]
Revenues:
Product	206,244	175,052
Service	51,205	47,418
Other	13,882	16,302
Revenue	271,331	238,772
Expenses:
Cost of products sold	175,084	157,378
Operating	42,499	44,976
General and administrative	12,942	12,644
Depreciation and amortization	14,793	16,407
Loss (gain) on disposal of long-lived assets, net	255	1,059
Total expenses	245,573	232,464
Earnings from equity method investments	20,839	20,864
Loss on issuance of common units by equity method investee	0
Operating income	46,597	27,172
Other expenses (income), net:
Interest expense	11,746	8,444
Foreign currency transaction loss (gain)	1,469	(519)
Loss (gain) on sale or impairment of equity method investment	0	0
Other income, net	(187)	(65)
Total other expenses, net	13,028	7,860
Income (loss) from continuing operations before income taxes	33,569	19,312
Income tax expense (benefit)	1,978	2,035
Income (loss) from continuing operations	31,591
Loss from discontinued operations, net of income taxes	0
Net income (loss)	31,591	17,277
Less: net income attributable to noncontrolling interests	9,020	4,310
Net income (loss) attributable to SemGroup	22,571	12,967
Other comprehensive loss, net of income taxes	16,141	(17,706)
Comprehensive income (loss)	47,732	(429)
Less: comprehensive income attributable to noncontrolling interests	9,020	4,310
Comprehensive income (loss) attributable to SemGroup	38,712	(4,739)
Consolidation, Eliminations [Member]
Revenues:
Product	(2,746)	(5,974)
Service	0	0
Other	0	0
Revenue	(2,746)	(5,974)
Expenses:
Cost of products sold	(2,746)	(5,974)
Operating	0	0
General and administrative	0	0
Depreciation and amortization	0	0
Loss (gain) on disposal of long-lived assets, net	0	0
Total expenses	(2,746)	(5,974)
Earnings from equity method investments	(23,538)	(27,638)
Loss on issuance of common units by equity method investee	0
Operating income	(23,538)	(27,638)
Other expenses (income), net:
Interest expense	(237)	(766)
Foreign currency transaction loss (gain)	0	0
Loss (gain) on sale or impairment of equity method investment	0	0
Other income, net	237	766
Total other expenses, net	0	0
Income (loss) from continuing operations before income taxes	(23,538)	(27,638)
Income tax expense (benefit)	0	0
Income (loss) from continuing operations	(23,538)
Loss from discontinued operations, net of income taxes	0
Net income (loss)	(23,538)	(27,638)
Less: net income attributable to noncontrolling interests	0	0
Net income (loss) attributable to SemGroup	(23,538)	(27,638)
Other comprehensive loss, net of income taxes	0	0
Comprehensive income (loss)	(23,538)	(27,638)
Less: comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to SemGroup	$ (23,538)	$ (27,638)