Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5618551-113959

+ Details

Name:	us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5618551-113959

+ Details

Name:	us-gaap_DerivativeGainOnDerivative
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Indicates line item in statement of income or comprehensive income that includes gain from derivative.

+ References

+ Details

Name:	us-gaap_DerivativeGainStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Amount of decrease in the fair value of derivatives recognized in the income statement.

+ References

+ Details

Name:	us-gaap_DerivativeLossOnDerivative
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Indicates line item in statement of income or comprehensive income that includes loss from derivative.

+ References

+ Details

Name:	us-gaap_DerivativeLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

+ Details

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

- Details

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_PriceRiskDerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_EnergyAxis=us-gaap_ElectricityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_EnergyAxis=srt_NaturalGasReservesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Risk Management and Derivatives: Derivatives Not Designated as Hedge Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Derivative [Line Items]
Derivative, Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]			Fuel, purchased power and cost of natural gas sold	Fuel, purchased power and cost of natural gas sold
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]			Fuel, purchased power and cost of natural gas sold	Fuel, purchased power and cost of natural gas sold
Regulatory assets	$ 706,206		$ 706,206		$ 796,599
Gas price derivatives
Derivative [Line Items]
Regulatory assets	10,776		10,776		$ 2,584
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 1,617	$ 6,498	2,779	$ 3,558
Not Designated as Hedging Instrument \| Electricity
Derivative [Line Items]
Derivative, Loss on Derivative			0	2,628
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]
Derivative, Gain on Derivative	$ 0	$ 2,494
Not Designated as Hedging Instrument \| Natural Gas
Derivative [Line Items]
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]	Fuel, purchased power and cost of natural gas sold	Fuel, purchased power and cost of natural gas sold
Derivative, Gain on Derivative	$ 1,617	$ 4,004	$ 2,779	$ 6,186