REVENUE FROM CONTRACTS WITH CUSTOMERS (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract with liability	$ 927,191		$ 927,191		$ 864,360
Contract with liability recognized	234,411	$ 183,644	564,833	$ 424,129
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract asset	80,501		80,501		$ 57,643
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining obligation	$ 991,328		$ 991,328
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining obligation period	1 year		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining obligation	$ 1,074,206		$ 1,074,206