XML 98 R82.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Financing: At-the-Market Equity Offering Program (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Feb. 27, 2020 | Dec. 31, 2021 | Dec. 31, 2019 | Jun. 30, 2021 | Aug. 03, 2020
At The Market Equity Offering Program Authorized Aggregate Value |  |  |  | $ 300,000 | $ 400,000
Private Placement |  |  |  |  |
Payments of Stock Issuance Costs | $ 1,000 |  |  |  |
Sale of Stock, Number of Shares Issued in Transaction | 1,200,000 |  |  |  |
Sale of Stock, Price Per Share | $ 81.77 |  |  |  |
Sale of Stock, Consideration Received on Transaction | $ 99,000 |  |  |  |
Common Stock |  |  |  |  |
At The Market Equity Offering Program Shares Issued |  | 1,812,197 | 1,328,332 |  |
At The Market Equity Program Proceeds from Sale of Stock |  | $ 119,000 | $ 99,000 |  |
Payments of Stock Issuance Costs |  | $ 1,100 | $ 1,200 |  |

X
- Definition At The Market Equity Offering Program authorized an aggregate value that the Company may, through its sales agents, offer and sell from time to time shares of its common stock. + References No definition available. + Details
Name: | bkh_AtTheMarketEquityOfferingProgramAuthorizedAggregateValue
Namespace Prefix: | bkh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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 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 http://asc.fasb.org/extlink&oid=123570139&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfStockIssuanceCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Cash received on stock transaction after deduction of issuance costs. + References No definition available. + Details
Name: | us-gaap_SaleOfStockConsiderationReceivedOnTransaction
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The number of shares issued or sold by the subsidiary or equity method investee per stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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