The percentage of unit holders approved by written consent for the simplification agreement on record date.

No definition available.

Name:	arlp_ApprovedShareHoldersConsentForSimplificationAgreementPercentage
Namespace Prefix:	arlp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of common units issued in an exchange transaction.

+ References

No definition available.

+ Details

Name:	arlp_NumberOfCommonUnitsIssuedInExchangeTransaction
Namespace Prefix:	arlp_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	arlp_OwnershipInterestsLineItems
Namespace Prefix:	arlp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of limited partner units issued to SGP in Simplification Transactions.

+ References

No definition available.

+ Details

Name:	arlp_PartnersCapitalAccountSgpSimplificationTransactionUnits
Namespace Prefix:	arlp_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

+ References

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units converted into shares of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

Name:	us-gaap_PartnersCapitalAccountUnitsConverted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_LimitedPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=arlp_ManagingGeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=arlp_AllianceResourcePartnersLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=arlp_AllianceResourceOperatingPartnersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=arlp_AllianceCoalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=arlp_SpecialGeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=arlp_AllianceHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis=arlp_PrivatePlacementExchangeTransactionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=arlp_SpecialGeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=arlp_ManagingGeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherSignificantNoncashTransactionsByUniqueDescriptionAxis=arlp_MergerAndSimplificationAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=arlp_AllianceHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ORGANIZATION AND PRESENTATION (Details) - shares			12 Months Ended
ORGANIZATION AND PRESENTATION (Details) - shares	May 31, 2018	Jul. 28, 2017	Dec. 31, 2018
Limited Partners' Capital
Ownership interests
Issuance of units to Owners of SGP in Simplification Transactions (in units)			1,322,388
MGP \| ARLP
Ownership interests
Ownership percentage by general partners			0.99%
MGP \| Intermediate Partnership
Ownership interests
Ownership percentage by general partners			1.0001%
MGP \| Alliance Coal
Ownership interests
Ownership percentage by general partners			0.001%
SGP \| AHGP
Ownership interests
Ownership interest held (as a percent)			34.48%
Exchange Transaction
Ownership interests
Common units issued in exchange			56,128,141
Exchange Transaction \| SGP
Ownership interests
Common units issued in exchange		28,141
Exchange Transaction \| MGP
Ownership interests
Common units issued in exchange		56,100,000
Exchange Transaction \| MGP \| ARLP
Ownership interests
Ownership percentage by general partners		0.99%
Exchange Transaction \| SGP \| ARLP
Ownership interests
Ownership percentage by general partners		0.01%
Simplification Transactions
Ownership interests
Issuance of units to Owners of SGP in Simplification Transactions (in units)			1,322,388
Simplification Transactions \| SGP
Ownership interests
Common units issued in exchange	29,188,997
Issuance of units to Owners of SGP in Simplification Transactions (in units)	1,322,388
Simplification Transactions \| Intermediate Partnership
Ownership interests
Ownership percentage by general partners	1.0001%
Simplification Transactions \| Alliance Coal
Ownership interests
Ownership percentage by general partners	0.001%
Simplification Transactions \| MGP \| Intermediate Partnership
Ownership interests
Ownership percentage by general partners	1.0001%
Simplification Transactions \| MGP \| Alliance Coal
Ownership interests
Ownership percentage by general partners	0.001%
Simplification Transactions \| SGP \| Intermediate Partnership
Ownership interests
Ownership percentage by general partners	1.0001%
Simplification Transactions \| SGP \| Alliance Coal
Ownership interests
Ownership percentage by general partners	0.001%
Simplification Transactions \| AHGP
Ownership interests
Approved written consent percent	68.00%
Units issued in exchange (in units)	1.4782
Simplification Transactions \| AHGP \| Intermediate Partnership
Ownership interests
Ownership percentage by general partners	1.0001%
Simplification Transactions \| AHGP \| Alliance Coal
Ownership interests
Ownership percentage by general partners	0.001%