COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands		3 Months Ended
	Apr. 29, 2016 aircraft People	Jun. 30, 2017 USD ($) aircraft People Facility Contract	Jun. 30, 2016 USD ($)	Apr. 01, 2016 People
Commitments And Contingencies [Line Items]
Operating leases rental expense | $		$ 58,700	$ 51,300
Lessor Leasing Arrangements, Operating Leases, Term of Contract		180 months
Lessor Leasing Arrangements, Operating Leases, Renewal Term		240 months
Named executive | People		2		1
Site Contingency, Number of Locations | Facility		3
Number of fatalities | People	11
Number of leased aircraft		91
Options [Abstract]
Number of signed client contracts | Contract		4
Passenger
Commitments And Contingencies [Line Items]
Number of fatalities | People	13
Crew
Commitments And Contingencies [Line Items]
Number of fatalities | People	2
Voluntary Separation Program [Member]
Commitments And Contingencies [Line Items]
Severance costs | $		$ 0	878
Involuntary Separation Program [Member]
Commitments And Contingencies [Line Items]
Severance costs | $		8,679	4,528
Direct cost [Member] | Voluntary Separation Program [Member]
Commitments And Contingencies [Line Items]
Severance costs | $		0	855
Direct cost [Member] | Involuntary Separation Program [Member]
Commitments And Contingencies [Line Items]
Severance costs | $		1,070	498
General and administrative expense [Member] | Voluntary Separation Program [Member]
Commitments And Contingencies [Line Items]
Severance costs | $		0	23
General and administrative expense [Member] | Involuntary Separation Program [Member]
Commitments And Contingencies [Line Items]
Severance costs | $		$ 7,609	4,030
Unionized Employees Concentration Risk [Member] | Workforce Subject to Collective Bargaining Arrangements [Member]
Commitments And Contingencies [Line Items]
Collective bargaining agreements and/or unions		53.00%
Employee agreement escalation rate		3.00%
Unionized Employees Concentration Risk [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]
Commitments And Contingencies [Line Items]
Collective bargaining agreements and/or unions		84.00%
Aircraft
Commitments And Contingencies [Line Items]
Operating leases rental expense | $		$ 51,700	$ 44,700
H225 Super Puma
Commitments And Contingencies [Line Items]
Number of aircraft operated	27
Number of aircraft owned	16
Number of leased aircraft	11
H225 Super Puma | Norway
Commitments And Contingencies [Line Items]
Number of aircraft operated	5
H225 Super Puma | Norway | Commercial Type Aircraft [Member]
Commitments And Contingencies [Line Items]
Number Of Aircraft Suspend Operations		1
H225 Super Puma | Norway | Search And Rescue Type Aircraft [Member]
Commitments And Contingencies [Line Items]
Number Of Aircraft Suspend Operations		4
H225 Super Puma | United Kingdom
Commitments And Contingencies [Line Items]
Number of aircraft operated	13
H225 Super Puma | United Kingdom | Commercial Type Aircraft [Member]
Commitments And Contingencies [Line Items]
Number Of Aircraft Suspend Operations		13
H225 Super Puma | Australia
Commitments And Contingencies [Line Items]
Number of aircraft operated	9
H225 Super Puma | Australia | Commercial Type Aircraft [Member]
Commitments And Contingencies [Line Items]
Number Of Aircraft Suspend Operations		6
H225 Super Puma | Australia | Search And Rescue Type Aircraft [Member]
Commitments And Contingencies [Line Items]
Number Of Aircraft Suspend Operations		3
Nine months ending March 31, 2017 to fiscal year 2018
Commitments And Contingencies [Line Items]
Number of leased aircraft		29
Fiscal year 2019 to fiscal year 2021
Commitments And Contingencies [Line Items]
Number of leased aircraft		48
Fiscal year 2022 to fiscal year 2024
Commitments And Contingencies [Line Items]
Number of leased aircraft		14
Cancellable Commitments [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required		5
Purchase Commitments - Total | $		$ 86,000
Deposit Assets | $		$ 4,500
Commitments
Analysis Of Aircraft Orders And Options [Line Items]
Start of period		32
Aircraft delivered		(3)
End of period		29
Options [Member]
Analysis Of Aircraft Orders And Options [Line Items]
Start of period		4
Aircraft delivered		0
End of period		4
Aircraft
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due Remainder Of Fiscal Year		6
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Two		5
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Three		4
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Four		4
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Five And Thereafter		10
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required		29
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year | $		$ 63,884
Unrecorded Unconditional Purchase Obligation, Due within Two Years | $		94,804
Unrecorded Unconditional Purchase Obligation, Due within Three Years | $		74,118
Unrecorded Unconditional Purchase Obligation, Due within Four Years | $		71,124
Unrecorded Unconditional Purchase Obligation, Due within Five Years And After | $		128,857
Purchase Commitments - Total | $		$ 432,787
Options [Abstract]
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due Remainder Of Fiscal Year		0
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Two		2
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Three		2
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Four		0
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Five And Thereafter		0
Unrecorded Conditional Purchase Obligation Maximum Quantity Required		4
Unrecorded Conditional Purchase Obligatio Due In Remainder Of Fiscal Year | $		$ 0
Unrecorded Conditional Purchase Obligation Balance On Second Anniversary | $		44,181
Unrecorded Conditional Purchase Obligation Balance On Third Anniversary | $		31,536
Unrecorded Conditional Purchase Obligation Balance On Fourth Anniversary | $		0
Unrecorded Conditional Purchase Obligation Due within Five Years And After | $		0
Aircraft Purchase Options - Total | $		$ 75,717
Aircraft | Medium aircraft
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due Remainder Of Fiscal Year		2
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Two		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Three		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Four		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Five And Thereafter		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required		2
Aircraft | Large aircraft
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due Remainder Of Fiscal Year		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Two		5
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Three		4
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Four		4
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Five And Thereafter		10
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required		23
Options [Abstract]
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due Remainder Of Fiscal Year		0
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Two		2
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Three		2
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Four		0
Unrecorded Conditional Purchase Obligation, Maximum Quantity Required, Due In Year Five And Thereafter		0
Unrecorded Conditional Purchase Obligation Maximum Quantity Required		4
Aircraft | Medium and Large
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year | $		$ 995
Unrecorded Unconditional Purchase Obligation, Due within Two Years | $		94,804
Unrecorded Unconditional Purchase Obligation, Due within Three Years | $		74,118
Unrecorded Unconditional Purchase Obligation, Due within Four Years | $		71,124
Unrecorded Unconditional Purchase Obligation, Due within Five Years And After | $		128,857
Purchase Commitments - Total | $		$ 369,898
Aircraft | U.K. SAR
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due Remainder Of Fiscal Year		4
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Two		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Three		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Four		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required, Due In Year Five And Thereafter		0
Unrecorded Unconditional Purchase Obligation, Minimum Quantity Required		4
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year | $		$ 62,889
Unrecorded Unconditional Purchase Obligation, Due within Two Years | $		0
Unrecorded Unconditional Purchase Obligation, Due within Three Years | $		0
Unrecorded Unconditional Purchase Obligation, Due within Four Years | $		0
Unrecorded Unconditional Purchase Obligation, Due within Five Years And After | $		0
Purchase Commitments - Total | $		62,889
Other Commitments
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Purchase Commitments - Total | $		65,200
Minimum
Commitments And Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss | $		4,000
Maximum
Commitments And Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss | $		6,000
VIH Aerospace
Commitments And Contingencies [Line Items]
Related Party Transaction, Purchases from Related Party | $		4,500
Costs and Expenses, Related Party | $		$ 100
VIH Aerospace | S-92
Commitments And Contingencies [Line Items]
Number of leased aircraft		6
VIH Aerospace | AW139
Commitments And Contingencies [Line Items]
Number of leased aircraft		1