XML 64 R48.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Business Description And Significant Accounting Policies: Investments (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2020 | Sep. 30, 2019 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Feb. 28, 2019
Investment [Line Items] |  |  |  |  |  |
Assets Held For Sale Used to Acquire Other Investments |  |  |  |  |  | $ 28,000
Impairment of investment | $ 6,900 | $ 20,000 | $ 0 | $ 6,859 | $ 19,741 |
Investments |  |  | 15,481 | 15,810 |  |
Investment in privately held oil and gas company |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |
Investments |  |  | 1,500 | 1,500 |  |
Cash surrender value of life insurance contracts |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |
Investments |  |  | 12,365 | 13,628 |  |
Other investments |  |  |  |  |  |
Investment [Line Items] |  |  |  |  |  |
Investments |  |  | $ 1,616 | $ 682 |  |

X
- Definition Assets Used to Acquire Other Investments + References No definition available. + Details
Name: | bkh_AssetsUsedtoAcquireOtherInvestments
Namespace Prefix: | bkh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 + Details
Name: | us-gaap_OtherAssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CashSurrenderValueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_InvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |