COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended	17 Months Ended
	Mar. 31, 2016 USD ($) aircraft	Dec. 31, 2015 USD ($) aircraft Facility Agreements	Sep. 30, 2015 aircraft	Jun. 30, 2015 aircraft	Dec. 31, 2014 USD ($) aircraft	Dec. 31, 2015 USD ($) aircraft Facility Agreements	Dec. 31, 2014 USD ($) aircraft Agreements	Mar. 31, 2015 aircraft Employee	May. 31, 2017 USD ($) aircraft	Feb. 03, 2016 People	Jan. 29, 2016 USD ($)	Aug. 12, 2015 People
Commitments And Contingencies [Abstract]
Number of signed client contracts		9				9
Aircraft Delivered		(8)			(6)	(11)	(17)
Rent expense | $		$ 52,200			$ 46,300	$ 160,500	$ 114,800
Number of aircraft sale leaseback		0				0	14
Sale leaseback transaction, gross proceeds | $		$ 0				$ 0	$ 380,700
Number of agreements to leaseback aircraft | Agreements		0				0	14
Sale leaseback transaction lease terms, maximum						180 months
Sale leaseback transaction lease renewal option terms, maximum						240 months
Number of leased aircraft		84				84
Monthly rent payment | $						$ 14,362
Site contingency, number of locations | Facility		3				3
Number of fatalities, crew members | People												2
Number of fatalities, passengers | People												4
Number of surviving passengers | People												6
Loss contingency, range of possible loss, minimum | $		$ 7,000				$ 7,000
Loss contingency, range of possible loss, maximum | $		10,000				10,000
Subsequent event
Commitments And Contingencies [Abstract]
Deferral of capital expenditures due remainder of year | $											$ 9,000
NumberOfPassengersWaterLanding | People										9
NumberOfCrewWaterLanding | People										2
Voluntary Separation Program
Commitments And Contingencies [Abstract]
Voluntary separation program, number of employees offered | Employee								2,888
Voluntary separation program, number of employees acceptance | Employee								137
Severance costs | $		900				8,200
Voluntary Separation Program | Direct cost
Commitments And Contingencies [Abstract]
Severance costs | $		600				7,300
Voluntary Separation Program | General administrative expense
Commitments And Contingencies [Abstract]
Severance costs | $		300				900
Voluntary Separation Program | Forecast
Commitments And Contingencies [Abstract]
Severance costs | $									$ 100
Involuntary Separation Program
Commitments And Contingencies [Abstract]
Severance costs | $		6,400				12,800
Involuntary Separation Program | Subsequent event
Commitments And Contingencies [Abstract]
Severance costs | $	$ 900
Involuntary Separation Program | Direct cost
Commitments And Contingencies [Abstract]
Severance costs | $		2,200				4,700
Involuntary Separation Program | General administrative expense
Commitments And Contingencies [Abstract]
Severance costs | $		$ 4,200				$ 8,100
Unionized Employees Concentration Risk | Workforce Subject to Collective Bargaining Arrangements
Commitments And Contingencies [Abstract]
Concentration risk, percentage						49.00%
Collective bargaining agreements, maximum annual escalation per employee, percent						6.00%
Unionized Employees Concentration Risk | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year
Commitments And Contingencies [Abstract]
Concentration risk, percentage						21.00%
Commitments
Commitments And Contingencies [Abstract]
Number of contingent aircraft		17				17
Beginning of quarter	37	41	46	45		45			37
Aircraft Delivered		(4)	(1)	(2)
Exercised options		0	0	3
Expired options		0	0	0
Reclassification		0	(4)	0
End of quarter		37	41	46		37		45
Options
Commitments And Contingencies [Abstract]
Beginning of quarter	16	21	21	30		30			16
Aircraft Delivered		0	0	0
Exercised options		0	0	(3)
Expired options		(5)	(4)	(6)
Reclassification		0	4	0
End of quarter		16	21	21		16		30
Other Commitments
Commitments And Contingencies [Abstract]
Purchase commitments | $		$ 398,800				$ 398,800
Aircraft
Commitments And Contingencies [Abstract]
Number of aircraft purchase commitments, due remainder of fiscal year		1				1
Number of aircraft purchase commitments, due in two years		14				14
Number of aircraft purchase commitments, due in three years		9				9
Number of aircraft purchase commitments, due in four years		4				4
Number of aircraft purchase commitments, due in five years and after		9				9
Number of aircraft purchase commitments		37				37
Purchase commitments, due remainder of year | $		$ 13,222				$ 13,222
Purchase commitments, Due within Two Years | $		122,273				122,273
Purchase commitments, Due within Three Years | $		121,411				121,411
Purchase commitments, Due within Four Years | $		60,683				60,683
Purchase commitments, Due within Five Years And After | $		109,755				109,755
Purchase commitments | $		$ 427,344				$ 427,344
Number of aircraft purchase options, due remainder of fiscal year		0				0
Number of aircraft purchase options, due in two years		0				0
Number of aircraft purchase options, due in three years		14				14
Number of aircraft purchase options, due in four years		2				2
Number of aircraft purchase options, due in five years and after		0				0
Number of aircraft purchase options		16				16
Aircraft purchase options, due remainder of year | $		$ 3,783				$ 3,783
Aircraft purchase options, due in two years | $		68,619				68,619
Aircraft purchase options, due in three years | $		205,096				205,096
Aircraft purchase options, due in four years | $		30,409				30,409
Aircraft purchase options, due in five years and after | $		0				0
Aircraft purchase options | $		$ 307,907				$ 307,907
Three months ending March 31, 2016 to fiscal year 2017
Commitments And Contingencies [Abstract]
Number of leased aircraft		6				6
Monthly rent payment | $						$ 1,052
Fiscal year 2018 to fiscal year 2020
Commitments And Contingencies [Abstract]
Number of leased aircraft		52				52
Monthly rent payment | $						$ 9,928
Fiscal year 2021 to fiscal year 2024
Commitments And Contingencies [Abstract]
Number of leased aircraft		26				26
Monthly rent payment | $						$ 3,382
SikorskyS76C [Member]
Commitments And Contingencies [Abstract]
NumberOfAircraftSuspendOperations						16
Medium aircraft
Commitments And Contingencies [Abstract]
Aircraft Delivered		0			(2)	(1)	(5)
Medium aircraft | Aircraft
Commitments And Contingencies [Abstract]
Number of aircraft purchase commitments, due remainder of fiscal year		0				0
Number of aircraft purchase commitments, due in two years		10				10
Number of aircraft purchase commitments, due in three years		0				0
Number of aircraft purchase commitments, due in four years		0				0
Number of aircraft purchase commitments, due in five years and after		0				0
Number of aircraft purchase commitments		10				10
Number of aircraft purchase options, due remainder of fiscal year		0				0
Number of aircraft purchase options, due in two years		0				0
Number of aircraft purchase options, due in three years		7				7
Number of aircraft purchase options, due in four years		0				0
Number of aircraft purchase options, due in five years and after		0				0
Number of aircraft purchase options		7				7
Large aircraft
Commitments And Contingencies [Abstract]
Aircraft Delivered		(8)			(4)	(10)	(12)
Large aircraft | Aircraft
Commitments And Contingencies [Abstract]
Number of aircraft purchase commitments, due remainder of fiscal year		0				0
Number of aircraft purchase commitments, due in two years		0				0
Number of aircraft purchase commitments, due in three years		5				5
Number of aircraft purchase commitments, due in four years		4				4
Number of aircraft purchase commitments, due in five years and after		9				9
Number of aircraft purchase commitments		18				18
Number of aircraft purchase options, due remainder of fiscal year		0				0
Number of aircraft purchase options, due in two years		0				0
Number of aircraft purchase options, due in three years		7				7
Number of aircraft purchase options, due in four years		2				2
Number of aircraft purchase options, due in five years and after		0				0
Number of aircraft purchase options		9				9
Medium and Large Aircrafts | Aircraft
Commitments And Contingencies [Abstract]
Purchase commitments, due remainder of year | $		$ 2,141				$ 2,141
Purchase commitments, Due within Two Years | $		64,440				64,440
Purchase commitments, Due within Three Years | $		66,266				66,266
Purchase commitments, Due within Four Years | $		60,683				60,683
Purchase commitments, Due within Five Years And After | $		109,755				109,755
Purchase commitments | $		$ 303,285				$ 303,285
U.K. SAR configured aircraft | Aircraft
Commitments And Contingencies [Abstract]
Number of aircraft purchase commitments, due remainder of fiscal year		0				0
Number of aircraft purchase commitments, due in two years		4				4
Number of aircraft purchase commitments, due in three years		4				4
Number of aircraft purchase commitments, due in four years		0				0
Number of aircraft purchase commitments, due in five years and after		0				0
Number of aircraft purchase commitments		8				8
Purchase commitments, due remainder of year | $		$ 2,228				$ 2,228
Purchase commitments, Due within Two Years | $		57,833				57,833
Purchase commitments, Due within Three Years | $		55,145				55,145
Purchase commitments, Due within Four Years | $		0				0
Purchase commitments, Due within Five Years And After | $		0				0
Purchase commitments | $		$ 115,206				$ 115,206
Other SAR configured aircraft | Aircraft
Commitments And Contingencies [Abstract]
Number of aircraft purchase commitments, due remainder of fiscal year		1				1
Number of aircraft purchase commitments, due in two years		0				0
Number of aircraft purchase commitments, due in three years		0				0
Number of aircraft purchase commitments, due in four years		0				0
Number of aircraft purchase commitments, due in five years and after		0				0
Number of aircraft purchase commitments		1				1
Purchase commitments, due remainder of year | $		$ 8,853				$ 8,853
Purchase commitments, Due within Two Years | $		0				0
Purchase commitments, Due within Three Years | $		0				0
Purchase commitments, Due within Four Years | $		0				0
Purchase commitments, Due within Five Years And After | $		0				0
Purchase commitments | $		8,853				8,853
Aircraft
Commitments And Contingencies [Abstract]
Rent expense | $		$ 45,600			$ 40,100	$ 139,500	$ 95,000