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Note 18 - Segment of Business - Summary of Reportable Segments Operations (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | Dec. 31, 2023
Electric operations(i) |  | $ 90,914 | $ 161,194 | $ 200,586 | $ 349,528 |
Operating Expense |  | 98,200 | 138,950 | 205,139 | 298,051 |
Income (loss) from operations |  | (7,286) | 22,244 | (4,553) | 51,477 |
Depreciation |  | 13,649 | 17,169 | 29,092 | 35,145 |
Assets |  | 595,169 | 599,889 | 595,169 | 599,889 | $ 589,780
Capital Expenditures |  | 13,170 | 17,128 | 28,044 | 30,610 |
Revenue |  | 90,914 | 161,194 | 200,586 | 349,528 |
Delivered energy |  | 1,267 | 1,603 | 2,554 | 2,943 |
Electric Operations [Member] |  |  |  |  |  |
Electric operations(i) | [1] | 57,020 | 71,103 | 115,932 | 163,597 |
Operating Expense |  | 50,232 | 61,847 | 93,897 | 135,636 |
Income (loss) from operations |  | 6,788 | 9,256 | 22,035 | 27,961 |
Depreciation |  | 4,698 | 4,675 | 9,395 | 9,350 |
Assets |  | 220,511 | 216,665 | 220,511 | 216,665 |
Capital Expenditures |  | 5,277 | 2,683 | 11,519 | 3,526 |
Revenue | [1] | 57,020 | 71,103 | 115,932 | 163,597 |
Amortization of contract liability |  | 12,080 | 19,555 | 24,868 | 52,902 |
Electric Operations [Member] | Energy Capacity [Member] |  |  |  |  |  |
Electric operations(i) |  | 16,873 | 17,155 | 28,646 | 33,125 |
Revenue |  | 16,873 | 17,155 | 28,646 | 33,125 |
Electric Operations [Member] | Delivered Energy [Member] |  |  |  |  |  |
Delivered energy |  | 27,893 | 34,307 | 62,087 | 77,382 |
Electric Operations [Member] | Other Operating Revenue [Member] |  |  |  |  |  |
Delivered energy |  | 174 | 86 | 331 | 188 |
Coal Operations [Member] |  |  |  |  |  |
Electric operations(i) |  | 46,429 | 113,098 | 113,299 | 208,371 |
Operating Expense |  | 57,750 | 86,735 | 136,077 | 168,920 |
Income (loss) from operations |  | (11,321) | 26,363 | (22,778) | 39,451 |
Depreciation |  | 8,930 | 12,466 | 19,658 | 25,741 |
Assets |  | 367,807 | 387,653 | 367,807 | 387,653 |
Capital Expenditures |  | 7,560 | 14,445 | 16,192 | 27,084 |
Revenue |  | 46,429 | 113,098 | 113,299 | 208,371 |
Corporate Segment and Other Operating Segment [Member] |  |  |  |  |  |
Electric operations(i) |  | (12,535) | (23,007) | (28,645) | (22,440) |
Operating Expense |  | (9,782) | (9,632) | (24,835) | (6,505) |
Income (loss) from operations |  | (2,753) | (13,375) | (3,810) | (15,935) |
Depreciation |  | 21 | 28 | 39 | 54 |
Assets |  | 6,851 | (4,429) | 6,851 | (4,429) |
Capital Expenditures |  | 333 | 0 | 333 | 0 |
Revenue |  | $ (12,535) | $ (23,007) | $ (28,645) | $ (22,440) |
[1] | Electric operations revenue as of each period presented were comprised of the components noted below (in thousands)

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