PROPERTY AND EQUIPMENT AND ASSETS HELD FOR SALE (Details) (USD $)	3 Months Ended								12 Months Ended				3 Months Ended	1 Months Ended
	Mar. 31, 2015 aircraft	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014 aircraft	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2015 aircraft	Mar. 31, 2014 aircraft	Mar. 31, 2013 aircraft	Mar. 31, 2016	Jun. 30, 2015	Apr. 30, 2015 aircraft
Property, Plant and Equipment [Line Items]
Number of aircraft added									21	21	19
Capital expenditures									$ 601,834,000	$ 628,613,000	$ 571,425,000
Number of aircraft sold or disposed of									44	46	27
Proceeds from asset dispositions									414,859,000	289,951,000	314,847,000
Gain (loss) on disposal of assets	(10,300,000)	(26,300,000)	100,000	600,000	100,000	4,000,000	(3,100,000)	(1,700,000)	(35,849,000)	(722,000)	8,068,000
Number of aircraft impaired									27	11
Impairment charges on assets held for sale									36,057,000	6,814,000
Number of aircraft sale leaseback									14	14	11
Sale Leaseback Transaction, Gross Proceeds									380,700,000	246,400,000	255,800,000
Number of aircraft reclassed held for sale to property and equipment											4
Gain from aircraft reclassed from held for sale to property and eqiupment											8,700,000
Insurance Recoveries											4,700,000
Number of aircraft transferred to held for sale	15				36				15	36	16
Property, Plant and Equipment, Gross, Period Increase (Decrease)									(91,500,000)	(51,600,000)	(13,900,000)
Deferred Sale Leaseback Abstract [Abstract]
Proceeds from assignment of aircraft purchase agreements									0	106,113,000	0
Number Of Aircraft Assigned Future Payments									2	7
Deferred sale leaseback advance									69,680,000	60,194,000	0
Number Of Aircraft Movement Into (Out Of) Deferred Sale Leaseback Advance									(5)
Completion of deferred sale leaseback									183,688,000	0	0
Removal of Deferred Sale Leaseback Advance									182,600,000
Improper Capitalization Of Profit [Member] | Revenue [Member]
Property, Plant and Equipment [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount									(3,500,000)
Improper Capitalization Of Profit [Member] | Direct cost [Member]
Property, Plant and Equipment [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount									2,000,000
Improper Capitalization Of Profit [Member] | Depreciation and amortization [Member]
Property, Plant and Equipment [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount									(200,000)
Improper Capitalization Of Profit [Member] | Property, plant and equipment, net [Member]
Property, Plant and Equipment [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount									(4,400,000)
Improper Capitalization Of Profit [Member] | Long-term liabilities [Member]
Property, Plant and Equipment [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount									900,000
Cougar [Member]
Property, Plant and Equipment [Line Items]
Capital expenditures											190,900,000
Damage from fire, explosion or other hazard [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft sold or disposed of										2
Gain (loss) on disposal of assets									4,900,000	(11,100,000)
Insurance Recoveries									16,000,000	11,100,000
Insurance Settlement [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on disposal of assets											2,800,000
Other International And West Africa [Member]
Property, Plant and Equipment [Line Items]
Accelerated Depreciation									4,400,000
Other International And West Africa [Member] | Scenario, Forecast [Member]
Property, Plant and Equipment [Line Items]
Accelerated Depreciation												3,800,000
Assets Held For Sale [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft impaired									27	11	10
Impairment charges on assets held for sale									36,057,000	6,814,000	4,362,000
Number of aircraft									12	16
Assets held for sale	57,800,000				29,300,000				57,800,000	29,300,000
Older Large Aircraft [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft impaired									17
Impairment charges on assets held for sale	6,400,000
Older Large Aircraft [Member] | Australia [Member]
Property, Plant and Equipment [Line Items]
Accelerated Depreciation	6,200,000
Older Large Aircraft [Member] | Australia [Member] | Scenario, Forecast [Member]
Property, Plant and Equipment [Line Items]
Accelerated Depreciation													6,200,000
Number Of Aircraft In Exit Plan												4
Older Large Aircraft [Member] | Assets Held For Sale [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft sold or disposed of	13
Number of aircraft impaired		10
Impairment charges on assets held for sale		24,500,000
Prototype Aircraft [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft impaired									3
Impairment charges on assets held for sale									4,300,000
Prototype Aircraft [Member] | Subsequent Event [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft sold or disposed of														3
Medium Aircraft [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft added									7	10	2
Medium Aircraft [Member] | Other International And West Africa [Member]
Property, Plant and Equipment [Line Items]
Number Of Aircraft In Exit Plan									10
Large Aircraft [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft added									14	11	17
Fixed Wing Aircraft [Member] | Other International And West Africa [Member]
Property, Plant and Equipment [Line Items]
Number Of Aircraft In Exit Plan									1
Aircraft and related equipment [Member]
Property, Plant and Equipment [Line Items]
Capital expenditures									476,368,000	563,724,000	504,329,000
Gain (loss) on disposal of assets									208,000	6,092,000	3,708,000
Other Depreciable Assets [Member]
Property, Plant and Equipment [Line Items]
Capital expenditures									125,466,000	64,889,000	67,096,000
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Capital expenditures									$ 440,900,000	$ 529,400,000	$ 312,700,000