XML 56 R43.htm IDEA: XBRL DOCUMENT
v3.23.1

Financing: At-the-Market Equity Offering Program (Details) - USD ($) | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Number of shares issued | 445,578 | 55,707
Number of shares issued | 34,040 |
Common Stock |  |
Proceeds, (net of issuance costs) | $ 27,400 | $ 3,800
Average price per share | $ 62.21 | $ 68.79
Payments of Stock Issuance Costs | $ (300,000) | $ 0.0

X
- Definition At the market equity offering program average price per share. + References No definition available. + Details
Name: | bkh_AtTheMarketEquityOfferingProgramAveragePricePerShare
Namespace Prefix: | bkh_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition At The Market Equity Offering Program Shares Issued + References No definition available. + Details
Name: | bkh_AtTheMarketEquityOfferingProgramSharesIssued
Namespace Prefix: | bkh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition At the market equity offering program shares issued but not settled. + References No definition available. + Details
Name: | bkh_AtTheMarketEquityOfferingProgramSharesIssuedButNotSettled
Namespace Prefix: | bkh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition At The Market Equity Program Proceeds from Sale of Stock + References No definition available. + Details
Name: | bkh_AtTheMarketEquityProgramProceedsfromSaleofStock
Namespace Prefix: | bkh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow for cost incurred directly with the issuance of an equity security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfStockIssuanceCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |