BASIS OF PRESENTATION, CONSOLIDATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)	3 Months Ended
	Jun. 30, 2012 number	Jun. 30, 2011	Mar. 31, 2012
Foreign Currency [Line Items]
Revenue	$ 362,608,000	$ 321,105,000
Operating expense	(319,289,000)	(292,109,000)
Earnings from unconsolidated affiliates, net of losses	1,989,000	5,993,000
Income before provision for income taxes	30,376,000	27,825,000
Provision for income taxes	(6,180,000)	(6,606,000)
Net income	24,196,000	21,219,000
Total stockholders' investment	1,541,199,000		1,521,824,000
Foreign currency transaction gain/loss	(900,000)	200,000
Impact of Foreign Exchange Rates on Unconsolidated affiliates	(3,100,000)	600,000
Other Matters [Line Items]
Allowance For Doubtful Accounts Non-Affiliates	200,000		100,000
Allowance for doubtful accounts, affiliates	0		0
PropertyAndEquipmentLineItems
Impairment of Long-Lived Assets to be Disposed of	1,900,000
Number of Impairment of Long-Lived Assets to be Disposed of	7
Property, Plant and Equipment, Number of Aircraft Sold	4
Net loss from aircraft and other equipment sold	3,400,000
One British Pound Sterling Into U.S. Dollars [Member] | High [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.62	1.66
One British Pound Sterling Into U.S. Dollars [Member] | Average [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.58	1.63
One British Pound Sterling Into U.S. Dollars [Member] | Low [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.53	1.60
One British Pound Sterling Into U.S. Dollars [Member] | At period-end [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.57	1.61
One Euro Into U.S. Dollars [Member] | High [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.33	1.49
One Euro Into U.S. Dollars [Member] | Average [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.28	1.44
One Euro Into U.S. Dollars [Member] | Low [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.24	1.40
One Euro Into U.S. Dollars [Member] | At period-end [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.27	1.45
One Australian Dollar Into U.S. Dollars [Member] | High [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.04	1.09
One Australian Dollar Into U.S. Dollars [Member] | Average [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.01	1.06
One Australian Dollar Into U.S. Dollars [Member] | Low [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.97	1.03
One Australian Dollar Into U.S. Dollars [Member] | At period-end [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	1.03	1.07
One Nigerian Naira Into U.S. Dollars [Member] | High [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.0065	0.0066
One Nigerian Naira Into U.S. Dollars [Member] | Average [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.0063	0.0065
One Nigerian Naira Into U.S. Dollars [Member] | Low [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.0061	0.0064
One Nigerian Naira Into U.S. Dollars [Member] | At period-end [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.0062	0.0065
One Brazilian Real Into U.S. Dollars [Member] | High [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.5488	0.6405
One Brazilian Real Into U.S. Dollars [Member] | Average [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.5125	0.6274
One Brazilian Real Into U.S. Dollars [Member] | Low [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.4811	0.6106
One Brazilian Real Into U.S. Dollars [Member] | At period-end [Member]
Foreign Currency [Line Items]
Foreign currency exchange rates	0.4816	0.6380
Impact of Changes in Foreign Currency Exchange Rates [Member]
Foreign Currency [Line Items]
Revenue	(8,778,000)
Operating expense	9,699,000
Earnings from unconsolidated affiliates, net of losses	(3,690,000)
Non-operating expense	(1,192,000)
Income before provision for income taxes	(3,961,000)
Provision for income taxes	806,000
Net income	(3,155,000)
Cumulative translation adjustment	305,000
Total stockholders' investment	$ (2,850,000)