| Note 11 - Acquisition of Nestor Cables (Details Textual) € in Millions | 12 Months Ended | |||
|---|---|---|---|---|
| Jul. 26, 2022  USD ($) | Jul. 26, 2022  EUR (€) | Sep. 30, 2022  USD ($) | Sep. 30, 2023  USD ($) | |
| Goodwill, Ending Balance | $ 6,402,000 | $ 6,528,000 | ||
| Nestor Cables [Member] | ||||
| Business Acquisition, Percentage of Voting Interests Acquired | 100.00% | |||
| Business Combination, Consideration Transferred, Total | $ 8,000,000 | € 7.9 | ||
| Business Combination, Consideration Transferred, Liabilities Incurred | 7,800,000 | € 7.6 | ||
| Goodwill, Ending Balance | $ 1,762,000 | |||
| Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year) | 12 years 9 months 25 days | 12 years 9 months 25 days | ||
| Nestor Cables [Member] | Selling, General and Administrative Expenses [Member] | ||||
| Business Combination, Acquisition Related Costs | $ 1,600,000 | |||
| Nestor Cables [Member] | Approximate [Member] | ||||
| Goodwill, Ending Balance | $ 1,700,000 | |||
| Nestor Cables [Member] | Revolving Credit Facility [Member] | ||||
| Proceeds from Lines of Credit | $ 16,700,000 | |||
| X | ||||||||||
| 
- Definition Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
 | 
| X | ||||||||||
| 
- Definition Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |