BUSINESS SEGMENTS AND GEOGRAPHIC INFORMATION - Revenues from External Customers by Country (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Revenues	$ 296,171	$ 633,639	$ 542,548	$ 1,248,296
United States
Segment Reporting Information [Line Items]
Revenues	280,757	581,520	516,201	1,148,335
Argentina
Segment Reporting Information [Line Items]
Revenues	6,979	29,682	8,532	70,291
Bahrain
Segment Reporting Information [Line Items]
Revenues	6,921	10,383	14,470	15,067
United Arab Emirates
Segment Reporting Information [Line Items]
Revenues	0	6,280	990	6,453
Colombia
Segment Reporting Information [Line Items]
Revenues	946	4,905	1,375	5,901
Other Foreign
Segment Reporting Information [Line Items]
Revenues	$ 568	$ 869	$ 980	$ 2,249