REVENUE RECOGNITION Remaining Performance Obligations (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	$ 220,800
Revenue, Remaining Performance Obligation, Rolling Year Two	245,387
Revenue, Remaining Performance Obligation, Rolling Year Three	200,077
Revenue, Remaining Performance Obligation, Rolling Year Four	189,496
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	479,896
Revenue, Remaining Performance Obligation, Amount	$ 1,335,656
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	$ 217,866
Revenue, Remaining Performance Obligation, Rolling Year Two	245,032
Revenue, Remaining Performance Obligation, Rolling Year Three	200,077
Revenue, Remaining Performance Obligation, Rolling Year Four	189,496
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	479,896
Revenue, Remaining Performance Obligation, Amount	1,332,367
Fixed Wing Service Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	2,934
Revenue, Remaining Performance Obligation, Rolling Year Two	355
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	$ 3,289