BASIS OF PRESENTATION, CONSOLIDATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)	3 Months Ended			6 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Mar. 31, 2011
Foreign Currency [Line Items]
Revenue		$ 330,992,000	$ 312,559,000	$ 652,097,000	$ 604,797,000
Operating expense		(315,749,000)	(265,613,000)	(607,858,000)	(519,188,000)
Earnings from unconsolidated affiliates, net of losses		(4,037,000)	4,716,000	1,956,000	4,014,000
Income before benefit (provision) for income taxes		1,016,000	42,164,000	28,841,000	71,612,000
Benefit (provision) for income taxes		1,945,000	(3,316,000)	(4,661,000)	(11,856,000)
Net income		2,961,000	38,848,000	24,180,000	59,756,000
Total stockholders' investment		1,524,852,000		1,524,852,000		1,518,775,000
Foreign currency transaction gain/loss		(100,000)	(100,000)	200,000	(200,000)
Gain on sales of joint ventures				0	(572,000)
Allowance for doubtful accounts, non-affiliates		100,000		100,000		100,000
Allowance for doubtful accounts, affiliates		0		0		0
Impairment of inventories		24,610,000	0	24,610,000	0
Dormant, obsolete and excess inventory		48,800,000		48,800,000
Loss on sale of inventory		1,000,000		1,000,000
Impairment from abandonment of certain assets		2,700,000		2,700,000
Lease termination costs	100,000
Impairment of held for sale aircraft		400,000		400,000
Loss on disposal of fixed wing aircraft		1,100,000		1,100,000
One British Pound Sterling Into U.S. Dollars [Member] | High [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.66	1.60	1.66	1.60
One British Pound Sterling Into U.S. Dollars [Member] | High [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.66	1.60	1.66	1.60
One British Pound Sterling Into U.S. Dollars [Member] | Average [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.61	1.55	1.61	1.55
One British Pound Sterling Into U.S. Dollars [Member] | Average [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.62	1.52	1.62	1.52
One British Pound Sterling Into U.S. Dollars [Member] | Low [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.53	1.51	1.53	1.51
One British Pound Sterling Into U.S. Dollars [Member] | Low [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.53	1.43	1.53	1.43
One British Pound Sterling Into U.S. Dollars [Member] | At period-end [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.56	1.58	1.56	1.58
One British Pound Sterling Into U.S. Dollars [Member] | At period-end [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.56	1.58	1.56	1.58
One Euro Into U.S. Dollars [Member] | High [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.45	1.37	1.45	1.37
One Euro Into U.S. Dollars [Member] | High [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.49	1.37	1.49	1.37
One Euro Into U.S. Dollars [Member] | Average [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.41	1.29	1.41	1.29
One Euro Into U.S. Dollars [Member] | Average [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.42	1.28	1.42	1.28
One Euro Into U.S. Dollars [Member] | Low [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.34	1.25	1.34	1.25
One Euro Into U.S. Dollars [Member] | Low [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.34	1.19	1.34	1.19
One Euro Into U.S. Dollars [Member] | At period-end [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.34	1.37	1.34	1.37
One Euro Into U.S. Dollars [Member] | At period-end [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.34	1.37	1.34	1.37
One Australian Dollar Into U.S. Dollars [Member] | High [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.10	0.97	1.10	0.97
One Australian Dollar Into U.S. Dollars [Member] | High [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.10	0.97	1.10	0.97
One Australian Dollar Into U.S. Dollars [Member] | Average [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.05	0.91	1.05	0.91
One Australian Dollar Into U.S. Dollars [Member] | Average [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		1.06	0.89	1.06	0.89
One Australian Dollar Into U.S. Dollars [Member] | Low [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.97	0.84	0.97	0.84
One Australian Dollar Into U.S. Dollars [Member] | Low [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.97	0.81	0.97	0.81
One Australian Dollar Into U.S. Dollars [Member] | At period-end [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.97	0.97	0.97	0.97
One Australian Dollar Into U.S. Dollars [Member] | At period-end [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.97	0.97	0.97	0.97
One Nigerian Naira Into U.S. Dollars [Member] | High [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0068	0.0068	0.0068	0.0068
One Nigerian Naira Into U.S. Dollars [Member] | High [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0068	0.0070	0.0068	0.0070
One Nigerian Naira Into U.S. Dollars [Member] | Average [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0066	0.0067	0.0066	0.0067
One Nigerian Naira Into U.S. Dollars [Member] | Average [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0065	0.0067	0.0065	0.0067
One Nigerian Naira Into U.S. Dollars [Member] | Low [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0063	0.0065	0.0063	0.0065
One Nigerian Naira Into U.S. Dollars [Member] | Low [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0063	0.0065	0.0063	0.0065
One Nigerian Naira Into U.S. Dollars [Member] | At period-end [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0064	0.0066	0.0064	0.0066
One Nigerian Naira Into U.S. Dollars [Member] | At period-end [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates		0.0064	0.0066	0.0064	0.0066
Impact of Changes in Foreign Currency Exchange Rates [Member] | Quarter To Date [Member]
Foreign Currency [Line Items]
Revenue		11,166,000
Operating expense		(9,810,000)
Earnings from unconsolidated affiliates, net of losses		(7,572,000)
Non-operating expense		(1,321,000)
Income before benefit (provision) for income taxes		(7,537,000)
Benefit (provision) for income taxes		1,209,000
Net income		(6,328,000)
Cumulative translation adjustment		(12,145,000)
Total stockholders' investment		(18,473,000)		(18,473,000)
Impact of Changes in Foreign Currency Exchange Rates [Member] | Year To Date [Member]
Foreign Currency [Line Items]
Revenue				29,334,000
Operating expense				(25,446,000)
Earnings from unconsolidated affiliates, net of losses				(7,550,000)
Non-operating expense				(1,068,000)
Income before benefit (provision) for income taxes				(4,730,000)
Benefit (provision) for income taxes				542,000
Net income				(4,188,000)
Cumulative translation adjustment				(11,360,000)
Total stockholders' investment		(15,548,000)		(15,548,000)
Foreign Currency Impact [Member]
Foreign Currency [Line Items]
Earnings from unconsolidated affiliates, net of losses		$ 7,500,000	$ 100,000	$ 8,100,000	$ 500,000