Lease Accounting (Maturity of Lessor Receipts) (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Direct Financing Lease
Total Net Lease Receipts	$ 8,600
Marine Transportation
Operating Leases
Remainder of 2019	20,350
2020	20,128
2021	0
2022	0
2023	0
Thereafter	0
Total Lease Receipts	40,478
Onshore Facilities & Transportation
Operating Leases
Remainder of 2019	900
2020	1,200
2021	1,200
2022	1,200
2023	1,200
Thereafter	5,300
Total Lease Receipts	11,000
Direct Financing Lease
Remainder of 2019	15,501
2020	20,668
2021	20,668
2022	20,668
2023	20,668
Thereafter	93,005
Total Lease Receipts	191,178
Less: Interest	(67,843)
Total Net Lease Receipts	$ 123,335

No definition available.

Name:	us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payments to be received by lessor in fifth fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payments to be received by lessor in fourth year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payments to be received by lessor in remainder of fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payments to be received by lessor after fifth fiscal year following latest statement of financial position date for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payments to be received by lessor in third fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease payments to be received by lessor in second fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Present value of lease payments not yet received by lessor and amount expected to be derived from underlying asset, following end of lease term guaranteed by lessee or other third party unrelated to lessor, from sales-type and direct financing leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919391-209981

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919379-209981

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFiveYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fourth fiscal year following latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in remainder of the fiscal year following latest fiscal year. Excludes interim and annual period when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919391-209981

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases after fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in third fiscal year following latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in second fiscal year following latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of undiscounted lease receivable in excess of discounted receivable for sales-type and direct financing leases.

+ References

+ Details

Name:	us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableUndiscountedExcessAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=gel_MarineTransportationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=gel_OnshoreFacilitiesandTransportationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: