BUSINESS SEGMENTS AND GEOGRAPHIC INFORMATION - Revenues from External Customers and Long-Lived Assets by Country (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Operating revenues	$ 2,756,607	$ 2,872,421	$ 2,058,944
Property, plant and equipment, net	3,016,277	2,921,695
United States
Segment Reporting Information [Line Items]
Operating revenues	2,558,814	2,656,617	1,920,026
Property, plant and equipment, net	2,752,325	2,813,707
Saudi Arabia
Segment Reporting Information [Line Items]
Property, plant and equipment, net	149,472	0
Argentina
Segment Reporting Information [Line Items]
Operating revenues	142,451	137,420	91,385
Property, plant and equipment, net	62,533	57,168
Bahrain
Segment Reporting Information [Line Items]
Operating revenues	17,990	15,401	16,986
Property, plant and equipment, net	19,807	7,657
Australia
Segment Reporting Information [Line Items]
Operating revenues	14,112	3,350	0
Property, plant and equipment, net	9,227	10,673
United Arab Emirates
Segment Reporting Information [Line Items]
Operating revenues	10,165	9,716	5,698
Property, plant and equipment, net	2,419	10,373
Columbia
Segment Reporting Information [Line Items]
Operating revenues	9,254	46,720	22,003
Property, plant and equipment, net	19,243	20,835
Other foreign
Segment Reporting Information [Line Items]
Operating revenues	3,821	3,197	$ 2,846
Property, plant and equipment, net	$ 1,251	$ 1,282