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v3.22.2.2

Note 2 - Summary of Significant Accounting Policies (Tables) | 12 Months Ended
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Sep. 30, 2022
Notes Tables |
Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] |
|  | September 30, 2022 |  |  | September 30, 2021 |
|  | Aggregate fair value |  |  | Amortized/ Adjusted cost basis |  |  | Pretax unrealized gains |  |  | Aggregate fair value |  |  | Amortized/ Adjusted cost basis |  |  | Pretax unrealized gains |
Marketable securities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stocks |  | $ | 275,529,000 |  |  | $ | 154,837,000 |  |  | $ | 120,692,000 |  |  | $ | 347,573,000 |  |  | $ | 103,480,000 |  |  | $ | 244,093,000 |
Valuation and Qualifying Accounts [Table Text Block] |
Description |  | Balance at Beginning of Year |  |  | Additions (Reductions) charged to Costs and Expenses |  |  | Accounts charged off less Recoveries |  |  | Balance at End of Year |
Fiscal 2022 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for doubtful accounts |  | $ | 250,000 |  |  | $ | 18,000 |  |  | $ | (18,000 | ) |  | $ | 250,000 |
Fiscal 2021 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for doubtful accounts |  | $ | 250,000 |  |  | $ | (3,000 | ) |  | $ | 3,000 |  |  | $ | 250,000 |

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