Note 12 - Segment Reporting - Reconciliation of Revenue from Segments to Consolidated (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Revenue from external customers | $ 47,168,000 | $ 36,910,000 | $ 82,644,000 | $ 71,140,000 |
| Revenue from internal customers (Clearfield, Inc.) | 0 | 0 | 0 | 0 |
| Net investment income | 1,589,000 | 1,849,000 | 3,332,000 | 3,918,000 |
| Interest expense | 69,000 | 102,000 | 169,000 | 228,000 |
| Depreciation and amortization | 1,876,000 | 1,920,000 | 3,711,000 | 3,572,000 |
| Stock based compensation | 1,288,000 | 1,012,000 | 2,427,000 | 2,284,000 |
| Income tax expense (benefit) | 455,000 | (2,083,000) | 29,000 | (3,034,000) |
| Net income (loss) | 1,327,000 | (5,911,000) | (579,000) | (11,179,000) |
| Capital expenditures | 2,394,000 | 1,971,000 | 4,033,000 | 4,389,000 |
| Intersegment Eliminations [Member] | ||||
| Revenue from external customers | 0 | 0 | 0 | 0 |
| Revenue from internal customers (Clearfield, Inc.) | (298,000) | (218,000) | (964,000) | (1,101,000) |
| Net investment income | (59,000) | (59,000) | (119,000) | (118,000) |
| Interest expense | (59,000) | (59,000) | (119,000) | (118,000) |
| Depreciation and amortization | 0 | 0 | 0 | 0 |
| Stock based compensation | 0 | 0 | 0 | 0 |
| Income tax expense (benefit) | 0 | 0 | 0 | 0 |
| Net income (loss) | 176,000 | 3,000 | 202,000 | (122,000) |
| Capital expenditures | 0 | 0 | 0 | 0 |
| Clearfield [Member] | Operating Segments [Member] | ||||
| Revenue from external customers | 40,621,000 | 27,600,000 | 70,319,000 | 55,700,000 |
| Revenue from internal customers (Clearfield, Inc.) | 0 | 0 | 0 | 0 |
| Net investment income | 1,648,000 | 1,906,000 | 3,451,000 | 4,032,000 |
| Interest expense | 0 | 0 | 0 | 0 |
| Depreciation and amortization | 1,547,000 | 1,551,000 | 3,061,000 | 2,848,000 |
| Stock based compensation | 1,171,000 | 940,000 | 2,221,000 | 2,161,000 |
| Income tax expense (benefit) | 722,000 | (1,825,000) | 775,000 | (2,408,000) |
| Net income (loss) | 2,339,000 | (5,001,000) | 1,845,000 | (8,384,000) |
| Capital expenditures | 1,067,000 | 1,806,000 | 2,390,000 | 3,093,000 |
| Nestor Cables [Member] | Operating Segments [Member] | ||||
| Revenue from external customers | 6,547,000 | 9,310,000 | 12,325,000 | 15,440,000 |
| Revenue from internal customers (Clearfield, Inc.) | 298,000 | 218,000 | 964,000 | 1,101,000 |
| Net investment income | 0 | 2,000 | 0 | 4,000 |
| Interest expense | 128,000 | 161,000 | 288,000 | 346,000 |
| Depreciation and amortization | 328,000 | 369,000 | 650,000 | 724,000 |
| Stock based compensation | 117,000 | 72,000 | 206,000 | 123,000 |
| Income tax expense (benefit) | (267,000) | (258,000) | (746,000) | (626,000) |
| Net income (loss) | (1,188,000) | (913,000) | (2,624,000) | (2,673,000) |
| Capital expenditures | $ 1,327,000 | $ 165,000 | $ 1,643,000 | $ 1,296,000 |
| X | ||||||||||
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of interest expense classified as operating and nonoperating. Includes, but is not limited to, cost of borrowing accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount, excluding interest income, of revenue not accounted for under Topic 606. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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