REVENUE RECOGNITION Remaining Performance Obligations (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	$ 251,019
Revenue, Remaining Performance Obligation, Rolling Year Two	240,420
Revenue, Remaining Performance Obligation, Rolling Year Three	186,194
Revenue, Remaining Performance Obligation, Rolling Year Four	176,615
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	268,028
Revenue, Remaining Performance Obligation, Amount	$ 1,122,276
Low
Disaggregation of Revenue [Line Items]
Revenue, Termination Period, Terms	30 days
High
Disaggregation of Revenue [Line Items]
Revenue, Termination Period, Terms	180 days
Helicopter Service Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	$ 249,470
Revenue, Remaining Performance Obligation, Rolling Year Two	240,042
Revenue, Remaining Performance Obligation, Rolling Year Three	186,194
Revenue, Remaining Performance Obligation, Rolling Year Four	176,615
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	268,028
Revenue, Remaining Performance Obligation, Amount	1,120,349
Fixed Wing Service Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	1,549
Revenue, Remaining Performance Obligation, Rolling Year Two	378
Revenue, Remaining Performance Obligation, Rolling Year Three	0
Revenue, Remaining Performance Obligation, Rolling Year Four	0
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	0
Revenue, Remaining Performance Obligation, Amount	$ 1,927