XML 141 R125.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Subsequent Events (Details) - MW | Jan. 01, 2022 | Dec. 31, 2021
--- | --- | ---
Purchase Power Contract, MEAN |  |
Subsequent Event [Line Items] |  |
Megawatts Sold Under Long-Term Contract |  | 20
Subsequent Event | Tri-State Generation and Transmission Association | Black Hills Energy - Colorado Electric |  |
Subsequent Event [Line Items] |  |
Megawatts Sold Under Long-Term Contract | 58 |
Subsequent Event | Purchase Power Contract, MEAN | Black Hills Energy - South Dakota Electric |  |
Subsequent Event [Line Items] |  |
Megawatts Sold Under Long-Term Contract | 20 |

X
- Definition Number of Megawatts Sold Under Long-Term Contract + References No definition available. + Details
Name: | bkh_NumberofMegawattsSoldUnderLongTermContract
Namespace Prefix: | bkh_
Data Type: | dtr-types:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SupplyCommitmentAxis=bkh_PurchasePowerContractMEANMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SupplyCommitmentAxis=bkh_TriStateGenerationAndTransmissionAssociationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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