FAIR VALUE MEASUREMENTS - Marketable Securities and Restricted Investments (Details) - Level 1 [Member] - Recurring Basis [Member] - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2026 |
Mar. 30, 2026 |
Mar. 31, 2025 |
Mar. 30, 2025 |
|
| FAIR VALUE MEASUREMENTS [Abstract] | ||||||
| Total marketable securities and restricted investments, beginning balance | $ 392 | $ 2,163 | $ 4,914 | $ 4,914 | $ 1,824 | $ 1,824 |
| Acquisition of controlling financial interest of Rubicon | 0 | 0 | (4,631) | 0 | ||
| Unrealized gain (loss) | (13) | 570 | 35 | 873 | ||
| Purchase of securities (net of sales) | 134 | 27 | 195 | 63 | ||
| Total marketable securities and restricted investments, ending balance | $ 513 | $ 2,760 | $ 513 | $ 513 | $ 2,760 | $ 2,760 |