REVENUE RECOGNITION Remaining Performance Obligations (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	$ 299,309
Revenue, Remaining Performance Obligation, Rolling Year Two	234,757
Revenue, Remaining Performance Obligation, Rolling Year Three	197,321
Revenue, Remaining Performance Obligation, Rolling Year Four	191,449
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	485,857
Revenue, Remaining Performance Obligation, Amount	$ 1,408,693
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	$ 295,833
Revenue, Remaining Performance Obligation, Rolling Year Two	234,757
Revenue, Remaining Performance Obligation, Rolling Year Three	197,321
Revenue, Remaining Performance Obligation, Rolling Year Four	191,449
Revenue, Remaining Performance Obligation, Rolling Year Five And Thereafter	485,857
Revenue, Remaining Performance Obligation, Amount	1,405,217
Fixed Wing Service Contracts [Member]
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Remainder Fiscal Year	3,476
Revenue, Remaining Performance Obligation, Rolling Year Two	0
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	$ 3,476