NOTES PAYABLE AND DEBT INSTRUMENTS - Revenue Bonds (Details) - Revenue Bonds lb in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 15, 2023 USD ($) lb	Jan. 31, 2022 USD ($)	Mar. 17, 2021 USD ($)	Oct. 07, 2020 USD ($) series supplier purchaser
Debt Instrument [Line Items]
Number of debt offering series | series								3
Debt instrument, discount								$ 5.5
Escrow deposit								50.0
Equity investments							$ 40.0	$ 60.0
Interest expense	$ 4.9	$ 4.9	$ 9.7	$ 9.7
Capitalized interest	2.8	$ 4.2	7.1	$ 8.5
Fair value of revenue bonds	$ 199.4		$ 199.4
Number of suppliers | supplier								1
Number of purchasers | purchaser								2,000
Escrow deposit, stated conditions satisfied, amount								$ 25.0
Cash required to maintain						$ 100.0
Operating revenue deposit requirement, percent								100.00%
Ironton Facility
Debt Instrument [Line Items]
Loan agreement, limited waiver terms, deposit in equity with the trustee					$ 87.3
Loan agreement, limited waiver terms, financing transaction milestone amount					$ 150.0
Loan agreement, limited waiver terms, production targets | lb					107
Loan agreement, limited waiver terms, deposit controlled by the trustee					$ 50.0
Loan agreement, limited waiver terms, deposit in equity amount to fund remaining construction costs					25.0
Loan agreement, limited waiver terms, deposit into capitalized interest accounts					12.3
Loan agreement, limited waiver terms, liquidity reserve escrow fund amount					50.0
Loan agreement, limited waiver terms, amount released from the trustee for investment					13.2
Minimum | Ironton Facility
Debt Instrument [Line Items]
Loan agreement, limited waiver terms, liquidity reserve escrow fund amount					$ 25.0