SEGMENT INFORMATION - Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenue	$ 318,220	$ 349,343	$ 651,396	$ 716,011
Europe Caspian
Segment Reporting Information [Line Items]
Revenue	180,442	203,801	370,080	423,981
Africa
Segment Reporting Information [Line Items]
Revenue	47,165	39,392	96,803	75,808
Americas
Segment Reporting Information [Line Items]
Revenue	62,263	57,079	120,564	110,083
Asia Pacific
Segment Reporting Information [Line Items]
Revenue	29,478	51,628	67,333	111,824
Corporate and other
Segment Reporting Information [Line Items]
Revenue	10	708	275	898
Intersegment elimination
Segment Reporting Information [Line Items]
Revenue	1,138	3,265	3,659	6,583
Intersegment elimination | Europe Caspian
Segment Reporting Information [Line Items]
Revenue	572	2,254	1,616	3,934
Intersegment elimination | Africa
Segment Reporting Information [Line Items]
Revenue	0	0	122	0
Intersegment elimination | Americas
Segment Reporting Information [Line Items]
Revenue	537	1,011	1,848	2,648
Intersegment elimination | Asia Pacific
Segment Reporting Information [Line Items]
Revenue	29	0	73	0
Intersegment elimination | Corporate and other
Segment Reporting Information [Line Items]
Revenue	0	0	0	1
External Customer
Segment Reporting Information [Line Items]
Revenue	318,220	349,343	651,396	716,011
External Customer | Europe Caspian
Segment Reporting Information [Line Items]
Revenue	179,870	201,547	368,464	420,047
External Customer | Africa
Segment Reporting Information [Line Items]
Revenue	47,165	39,392	96,681	75,808
External Customer | Americas
Segment Reporting Information [Line Items]
Revenue	61,726	56,068	118,716	107,435
External Customer | Asia Pacific
Segment Reporting Information [Line Items]
Revenue	29,449	51,628	67,260	111,824
External Customer | Corporate and other
Segment Reporting Information [Line Items]
Revenue	10	708	275	897
Revenue Not from Contract with Customer [Member]
Segment Reporting Information [Line Items]
Revenue	8,400	12,200	16,800	32,000
Revenue Not from Contract with Customer [Member] | Europe Caspian
Segment Reporting Information [Line Items]
Revenue	300	4,100	600	17,100
Revenue Not from Contract with Customer [Member] | Americas
Segment Reporting Information [Line Items]
Revenue	8,000	8,000	16,000	14,700
Revenue Not from Contract with Customer [Member] | Asia Pacific
Segment Reporting Information [Line Items]
Revenue	$ 100	$ 100	$ 200	$ 200