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| 0001130464-22-000021-index.html | 2022-08-04 12:05:55 | |
| 0001130464-22-000021.txt | 2022-08-04 12:05:55 | |
 0001130464-22-000021-xbrl.zip | 339213 | 2022-08-04 12:05:55 |
| bkh-20220630.htm | 2634205 | 2022-08-04 12:05:55 |
| bkh-20220630.xsd | 53332 | 2022-08-04 12:05:55 |
| bkh-20220630_cal.xml | 79874 | 2022-08-04 12:05:55 |
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| bkh-20220630_htm.xml | 2236706 | 2022-08-04 12:05:55 |
| bkh-20220630_lab.xml | 650564 | 2022-08-04 12:05:55 |
| bkh-20220630_pre.xml | 464364 | 2022-08-04 12:05:55 |
| bkhex-311q22022.htm | 13450 | 2022-08-04 12:05:55 |
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| bkhex-321q22022.htm | 6378 | 2022-08-04 12:05:55 |
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| bkhex-95q22022.htm | 17190 | 2022-08-04 12:05:55 |
| FilingSummary.xml | 40898 | 2022-08-04 12:05:55 |
| Financial_Report.xlsx | 108742 | 2022-08-04 12:05:55 |
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| report.css | 2767 | 2022-08-04 12:05:55 |
| Show.js | 1085 | 2022-08-04 12:05:55 |