XML 108 R83.htm IDEA: XBRL DOCUMENT
v3.20.4

PARTNERS' CAPITAL - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
Jun. 29, 2018 | May 31, 2018 | Dec. 31, 2020 | Dec. 31, 2018
Partners' capital |  |  |  |
Cash contribution by affiliated entity |  |  |  | $ 2,142
Affiliated entity controlled by Mr. Craft |  |  |  |
Partners' capital |  |  |  |
Contribution of units by affiliated entity (in units) | 467,018 |  |  |
Cash contribution by affiliated entity |  |  |  | $ 2,100
MGP | Intermediate Partnership |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  |  | 1.0001% |
MGP | Alliance Coal |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  |  | 0.001% |
Limited Partners' Capital |  |  |  |
Partners' capital |  |  |  |
Issuance of units to Owners of SGP in Simplification Transactions (in units) |  |  |  | 1,322,388
Repurchase and retire authorization |  | $ 100,000 |  |
Treasury units retired |  |  | $ 93,500 |
Number of units retired |  |  | 5,460,639 |
Repurchase price (in dollars per unit) |  |  | $ 17.12 |
Contribution of units by affiliated entity (in units) |  |  |  | (467,018)
Simplification Transactions | Intermediate Partnership |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  | 1.0001% |  |
Simplification Transactions | Alliance Coal |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  | 0.001% |  |
Simplification Transactions | SGP |  |  |  |
Partners' capital |  |  |  |
Issuance of units to Owners of SGP in Simplification Transactions (in units) |  | 1,322,388 |  |
Simplification Transactions | MGP | Intermediate Partnership |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  | 1.0001% |  |
Simplification Transactions | MGP | Alliance Coal |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  | 0.001% |  |
Simplification Transactions | SGP | Intermediate Partnership |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  | 1.0001% |  |
Simplification Transactions | SGP | Alliance Coal |  |  |  |
Partners' capital |  |  |  |
Ownership percentage by general partners |  | 0.001% |  |

X
- Definition Total contributions made by affiliate in units. + References No definition available. + Details
Name: | arlp_PartnersCapitalAccountContributionsByAffiliateUnits
Namespace Prefix: | arlp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- 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

X
- 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

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LimitedPartnersCapitalAccountLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow from an entity that is affiliated with the entity by means of direct or indirect ownership. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromContributionsFromAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
Name: | us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of decrease of par value, additional paid in capital (APIC) and retained earnings of common and preferred stock retired from treasury when treasury stock is accounted for under the cost method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 + Details
Name: | us-gaap_TreasuryStockRetiredCostMethodAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares of common and preferred stock retired from treasury during the period. + References Reference 1: 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=120397183&loc=d3e187085-122770 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
Name: | us-gaap_TreasuryStockSharesRetired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=arlp_AffiliatedEntityControlledByMrCraftMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=arlp_ManagingGeneralPartnerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=arlp_AllianceResourceOperatingPartnersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=arlp_AllianceCoalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | srt_CounterpartyNameAxis=arlp_SpecialGeneralPartnerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=arlp_SpecialGeneralPartnerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |