RESTRUCTURING CHARGES - Summary of Restructuring and Other Similar Costs (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 16,047
Operating Segments | North America Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	7,005
Operating Segments | Offshore Gulf of Mexico
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	1,254
Operating Segments | International Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	2,980
Operating Segments | Other
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	260
Corporate, Non-Segment
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	4,548
Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	19,530
Employee termination benefits | Operating Segments | North America Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	10,041
Employee termination benefits | Operating Segments | Offshore Gulf of Mexico
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	1,432
Employee termination benefits | Operating Segments | International Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	2,991
Employee termination benefits | Operating Segments | Other
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	321
Employee termination benefits | Corporate, Non-Segment
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	4,745
Stock-based compensation benefit
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	3,483
Stock-based compensation benefit | Operating Segments | North America Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	3,036
Stock-based compensation benefit | Operating Segments | Offshore Gulf of Mexico
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	178
Stock-based compensation benefit | Operating Segments | International Solutions
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	11
Stock-based compensation benefit | Operating Segments | Other
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	61
Stock-based compensation benefit | Corporate, Non-Segment
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 197