FAIR VALUE MEASUREMENT OF FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended			3 Months Ended		6 Months Ended
	Oct. 31, 2022	Apr. 30, 2022	Sep. 30, 2021	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) resulting from the change in the fair value of investments				$ 42,600	$ 16,700	$ 24,400	$ 64,500
Unrealized gain (loss) on investments				(3,000)		100
Revenue included in contract backlog						30,300
Geothermal Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other debt securities				27,300		27,300			$ 23,700
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities			$ 2,865	26,301	13,990	26,301	13,990	$ 25,800	23,745	$ 8,881
Galileo Technologies | Convertible Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate (as a percent)		5.00%
ADNOC Drilling
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments to acquire investments			$ 100,000
Investment balance (in shares)			159.7
Investments lockup period (in years)			3 years
ADNOC Drilling | ADNOC Drilling
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership percentage (as a percent)			1.00%
Tamboran Resources Limited
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments to acquire investments	$ 14,100
Investment shares acquired (in shares)	106.0
Tamboran Resources Limited | Tamboran Resources Limited
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership percentage (as a percent)	7.50%
Galileo Technologies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments to acquire investments		$ 33,000
Galileo Technologies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities			$ 500	$ 35,140	$ 3,500	$ 35,140	$ 3,500	$ 33,107	$ 33,565	$ 3,500