PROPERTY, PLANT AND EQUIPMENT, NET - Schedule of Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 407,063		$ 240,500
Less: accumulated depreciation	(108,309)		(100,902)
Construction in progress	321,913		195,542
Property, plant and equipment, net	620,667		335,140
Machineries and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	204,599		140,160
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	144,497		44,680
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	32,808		28,625
Fixtures and electronic equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	19,132		16,193
Motor vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 6,027		$ 10,842
China Phase 3.1
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 168,467