XML 110 R90.htm IDEA: XBRL DOCUMENT v3.25.3
FAIR VALUE MEASUREMENT OF FINANCIAL INSTRUMENTS - Schedule of Assets Measured at Fair Value (Details) - USD ($)
$ in Thousands
Sep. 30, 2025
Sep. 30, 2024
Short-term investments:    
Total short-term investments $ 21,302 $ 292,919
Recurring Fair Value Measurements    
Long-term investments:    
Non-qualified supplemental savings plan 17,662 15,633
Total 47,337 70,223
Recurring Fair Value Measurements | Investment in Tamboran    
Long-term investments:    
Investment in Tamboran 25,976 20,958
Recurring Fair Value Measurements | Other Equity Securities    
Long-term investments:    
Investment in Tamboran 1,449  
Recurring Fair Value Measurements | Investment in Galileo, net    
Long-term investments:    
Debt securities, investment 0 27,044
Recurring Fair Value Measurements | Geothermal debt securities, net    
Long-term investments:    
Debt securities, investment 2,000 2,000
Recurring Fair Value Measurements | Other debt securities    
Long-term investments:    
Debt securities, investment 250 4,588
Level 1    
Short-term investments:    
Total short-term investments 0 259,106
Level 1 | Recurring Fair Value Measurements    
Long-term investments:    
Non-qualified supplemental savings plan 17,662 15,633
Total 45,087 40,929
Level 1 | Recurring Fair Value Measurements | Investment in Tamboran    
Long-term investments:    
Investment in Tamboran 25,976 20,958
Level 1 | Recurring Fair Value Measurements | Other Equity Securities    
Long-term investments:    
Investment in Tamboran 1,449  
Level 1 | Recurring Fair Value Measurements | Investment in Galileo, net    
Long-term investments:    
Debt securities, investment 0 0
Level 1 | Recurring Fair Value Measurements | Geothermal debt securities, net    
Long-term investments:    
Debt securities, investment 0 0
Level 1 | Recurring Fair Value Measurements | Other debt securities    
Long-term investments:    
Debt securities, investment 0 4,338
Level 2    
Short-term investments:    
Total short-term investments 21,302 33,813
Level 2 | Recurring Fair Value Measurements    
Long-term investments:    
Non-qualified supplemental savings plan 0 0
Total 0 0
Level 2 | Recurring Fair Value Measurements | Investment in Tamboran    
Long-term investments:    
Investment in Tamboran 0 0
Level 2 | Recurring Fair Value Measurements | Other Equity Securities    
Long-term investments:    
Investment in Tamboran 0  
Level 2 | Recurring Fair Value Measurements | Investment in Galileo, net    
Long-term investments:    
Debt securities, investment 0 0
Level 2 | Recurring Fair Value Measurements | Geothermal debt securities, net    
Long-term investments:    
Debt securities, investment 0 0
Level 2 | Recurring Fair Value Measurements | Other debt securities    
Long-term investments:    
Debt securities, investment 0 0
Level 3    
Short-term investments:    
Total short-term investments 0 0
Level 3 | Recurring Fair Value Measurements    
Long-term investments:    
Non-qualified supplemental savings plan 0 0
Total 2,250 29,294
Level 3 | Recurring Fair Value Measurements | Investment in Tamboran    
Long-term investments:    
Investment in Tamboran 0 0
Level 3 | Recurring Fair Value Measurements | Other Equity Securities    
Long-term investments:    
Investment in Tamboran 0  
Level 3 | Recurring Fair Value Measurements | Investment in Galileo, net    
Long-term investments:    
Debt securities, investment 0  
Level 3 | Recurring Fair Value Measurements | Geothermal debt securities, net    
Long-term investments:    
Debt securities, investment 2,000 2,000
Level 3 | Recurring Fair Value Measurements | Other debt securities    
Long-term investments:    
Debt securities, investment 250 250
Corporate debt securities    
Short-term investments:    
Total short-term investments 21,302 33,813
Corporate debt securities | Level 1    
Short-term investments:    
Total short-term investments 0 0
Corporate debt securities | Level 2    
Short-term investments:    
Total short-term investments 21,302 33,813
Corporate debt securities | Level 3    
Short-term investments:    
Total short-term investments 0 0
U.S. government and federal agency securities    
Short-term investments:    
Total short-term investments   53,490
U.S. government and federal agency securities | Level 1    
Short-term investments:    
Total short-term investments   53,490
U.S. government and federal agency securities | Level 2    
Short-term investments:    
Total short-term investments   0
U.S. government and federal agency securities | Level 3    
Short-term investments:    
Total short-term investments   $ 0
Investment in ADNOC Drilling    
Short-term investments:    
Total short-term investments 205,616  
Investment in ADNOC Drilling | Level 1    
Short-term investments:    
Total short-term investments 205,616  
Investment in ADNOC Drilling | Level 2    
Short-term investments:    
Total short-term investments 0  
Investment in ADNOC Drilling | Level 3    
Short-term investments:    
Total short-term investments $ 0