Regulatory Matters: Rate Review (Details) $ in Thousands						3 Months Ended	9 Months Ended
	Jan. 01, 2022	Sep. 11, 2020 USD ($) mi	Jun. 01, 2020 USD ($) mi	May 19, 2020 USD ($)	Feb. 01, 2019 USD ($) utility	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Oct. 15, 2020 MW
Public Utilities, General Disclosures [Line Items]
Income Tax Benefit from Relieved TCJA Related Liabilities						$ 3,500	$ 4,000
Federal Energy Regulatory Commission (FERC) | Black Hills Wyoming and Wyoming Electric | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Number of Megawatts Capacity Purchased | MW								60
Public Utilities Term of Power Purchase Agreement	11 years
Rate Review Filed with the Regulatory Agency | Colorado Public Utilities Commission (CPUC) | Black Hills Energy, Colorado Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments | mi		7,000
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 13,500			$ 2,500
Public Utilities, Requested Equity Capital Structure, Percentage		50.00%
Public Utilities, Requested Debt Capital Structure, Percentage		50.00%
Public Utilities, Requested Return on Equity, Percentage		9.95%
Public Utilities, Number of Gas Distribution Territories Consolidating | utility					2
Public Utilities, Approved Rate Increase (Decrease), Amount				$ 600
Public Utilities, Approved Return on Equity, Percentage				9.20%
Rate Review Filed with the Regulatory Agency | Nebraska Publc Service Commission (NPSC) | Black Hills Energy, Nebraska Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments | mi			13,000
Public Utilities, Requested Rate Increase (Decrease), Amount			$ 17,300
Public Utilities, Requested Equity Capital Structure, Percentage			50.00%
Public Utilities, Requested Debt Capital Structure, Percentage			50.00%
Public Utilities, Requested Return on Equity, Percentage			10.00%
Public Utilities, State Statute Allows for Implementation of Interim Rates After Certain Number of Days Following Filing of Rate Review			90 days
System Safety and Integrity Rider Rate Review Filed with the Regulatory Agency | Colorado Public Utilities Commission (CPUC) | Black Hills Energy, Colorado Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Term of Rate Recovery		5 years
System Safety and Integrity Rider Rate Review Filed with the Regulatory Agency | Nebraska Publc Service Commission (NPSC) | Black Hills Energy, Nebraska Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Term of Rate Recovery			5 years