BUSINESS SEGMENTS AND GEOGRAPHIC INFORMATION - Reconciliation of Segment Assets to Consolidated Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Assets	$ 4,829,621	$ 5,839,515
Operating Segments
Segment Reporting Information [Line Items]
Assets	4,109,544	5,636,209
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Assets	720,077	203,306
North America Solutions | Operating Segments
Segment Reporting Information [Line Items]
Assets	3,812,718	5,284,141
Offshore Gulf of Mexico | Operating Segments
Segment Reporting Information [Line Items]
Assets	93,501	102,442
International Solutions | Operating Segments
Segment Reporting Information [Line Items]
Assets	181,181	217,094
Other | Operating Segments
Segment Reporting Information [Line Items]
Assets	22,144	32,532
Continuing Operations
Segment Reporting Information [Line Items]
Assets	4,829,621	5,839,515
Discontinued Operations
Segment Reporting Information [Line Items]
Assets	$ 0	$ 0