SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION BS (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Mar. 31, 2011
Balance Sheet [Line Items]
Cash and cash equivalents	$ 348,349	$ 261,550	$ 140,279	$ 116,361
Accounts receivable	266,872	286,220
Inventories	158,949	157,825	48,801
Assets held for sale	19,552	18,710	649
Prepaid expenses and other current assets	18,083	12,168
Total current assets	811,805	736,473
Intercompany investment	0	0
Investment in unconsolidated affiliates	214,620	205,100
Intercompany notes receivable	0	0
Land and buildings	84,068	80,835
Aircraft and equipment	2,064,285	2,099,642
Total property and equipment, at cost	2,148,353	2,180,477
Less - Accumulated depreciation and amortization	(463,913)	(457,702)
Total property and equipment, net	1,684,440	1,722,775
Goodwill	29,789	29,644
Other assets	44,814	46,371
Total assets	2,785,468	2,740,363
Accounts payable	55,650	56,084
Accrued liabilities	126,242	113,676
Current deferred taxes	15,165	15,070
Short Term Borrowings And Current Maturities Of Long Term Debt	18,750	14,375
Total current liabilities	215,807	199,205
Long-term debt, less current maturities	715,936	742,870
Intercompany notes payable	0	0
Accrued pension liabilities	112,221	111,742
Other liabilities and deferred credits	17,403	16,768
Deferred taxes	143,912	147,954
Common stock	365	363
Additional paid-in capital	717,347	703,628
Retained earnings	1,032,468	993,435
Accumulated other comprehensive income (loss)	(154,614)	(159,239)
Treasury shares	25,085	25,085
Stockholders' equity	1,570,481	1,513,102
Noncontrolling interests	9,708	8,722
Total stockholders' investment	1,580,189	1,521,824
Total liabilities and stockholders' investment	2,785,468	2,740,363
Parent Company [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	134,682	76,609	83,152	24,075
Accounts receivable	11,263	12,884
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	2,593	1,512
Total current assets	148,538	91,005
Intercompany investment	1,030,042	1,031,041
Investment in unconsolidated affiliates	9,532	2,378
Intercompany notes receivable	1,321,940	1,266,714
Land and buildings	801	801
Aircraft and equipment	22,311	13,969
Total property and equipment, at cost	23,112	14,770
Less - Accumulated depreciation and amortization	(8,827)	(6,705)
Total property and equipment, net	14,285	8,065
Goodwill	0	0
Other assets	24,976	111,442
Total assets	2,549,313	2,510,645
Accounts payable	2,848	3,130
Accrued liabilities	11,543	11,506
Current deferred taxes	(2,011)	(1,571)
Short Term Borrowings And Current Maturities Of Long Term Debt	18,750	14,375
Total current liabilities	31,130	27,440
Long-term debt, less current maturities	715,936	742,870
Intercompany notes payable	0	0
Accrued pension liabilities	0	0
Other liabilities and deferred credits	7,590	6,738
Deferred taxes	125,095	121,385
Common stock	365	363
Additional paid-in capital	717,347	703,628
Retained earnings	1,032,468	993,435
Accumulated other comprehensive income (loss)	(57,126)	(61,706)
Treasury shares	25,085	25,085
Stockholders' equity	1,667,969	1,610,635
Noncontrolling interests	1,593	1,577
Total stockholders' investment	1,669,562	1,612,212
Total liabilities and stockholders' investment	2,549,313	2,510,645
Guarantor Subsidiaries [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	3,529	3,155	2,536	5,233
Accounts receivable	80,485	97,732
Inventories	55,593	57,957
Assets held for sale	3,969	1,400
Prepaid expenses and other current assets	1,167	2,220
Total current assets	144,743	162,464
Intercompany investment	111,434	111,434
Investment in unconsolidated affiliates	150	150
Intercompany notes receivable	0	0
Land and buildings	48,788	48,855
Aircraft and equipment	874,351	880,643
Total property and equipment, at cost	923,139	929,498
Less - Accumulated depreciation and amortization	(190,556)	(186,876)
Total property and equipment, net	732,583	742,622
Goodwill	4,755	4,755
Other assets	1,209	2,416
Total assets	994,874	1,023,841
Accounts payable	13,832	26,384
Accrued liabilities	23,870	20,987
Current deferred taxes	31	(128)
Short Term Borrowings And Current Maturities Of Long Term Debt	0	0
Total current liabilities	37,733	47,243
Long-term debt, less current maturities	0	0
Intercompany notes payable	247,963	296,335
Accrued pension liabilities	0	0
Other liabilities and deferred credits	8,477	8,754
Deferred taxes	8,781	8,903
Common stock	4,996	4,996
Additional paid-in capital	9,290	9,290
Retained earnings	677,634	648,320
Accumulated other comprehensive income (loss)	0	0
Treasury shares	0	0
Stockholders' equity	691,920	662,606
Noncontrolling interests	0	0
Total stockholders' investment	691,920	662,606
Total liabilities and stockholders' investment	994,874	1,023,841
Non-Guarantor Subsidiaries [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	210,138	181,786	54,591	87,053
Accounts receivable	213,652	246,297
Inventories	103,356	99,868
Assets held for sale	15,583	17,310
Prepaid expenses and other current assets	52,417	27,394
Total current assets	595,146	572,655
Intercompany investment	0	0
Investment in unconsolidated affiliates	204,938	202,572
Intercompany notes receivable	0	(13,792)
Land and buildings	34,479	31,179
Aircraft and equipment	1,167,623	1,205,030
Total property and equipment, at cost	1,202,102	1,236,209
Less - Accumulated depreciation and amortization	(264,530)	(264,121)
Total property and equipment, net	937,572	972,088
Goodwill	25,034	24,889
Other assets	146,790	166,829
Total assets	1,909,480	1,925,241
Accounts payable	71,012	93,914
Accrued liabilities	133,340	102,006
Current deferred taxes	17,145	16,769
Short Term Borrowings And Current Maturities Of Long Term Debt	0	0
Total current liabilities	221,497	212,689
Long-term debt, less current maturities	0	0
Intercompany notes payable	1,088,411	1,057,622
Accrued pension liabilities	112,221	111,742
Other liabilities and deferred credits	141,604	161,168
Deferred taxes	10,036	17,666
Common stock	22,918	22,828
Additional paid-in capital	262,193	249,367
Retained earnings	28,281	30,335
Accumulated other comprehensive income (loss)	14,204	54,679
Treasury shares	0	0
Stockholders' equity	327,596	357,209
Noncontrolling interests	8,115	7,145
Total stockholders' investment	335,711	364,354
Total liabilities and stockholders' investment	1,909,480	1,925,241
Consolidations, Eliminations [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable	(38,528)	(70,693)
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	(38,094)	(18,958)
Total current assets	(76,622)	(89,651)
Intercompany investment	(1,141,476)	(1,142,475)
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	(1,321,940)	(1,252,922)
Land and buildings	0	0
Aircraft and equipment	0	0
Total property and equipment, at cost	0	0
Less - Accumulated depreciation and amortization	0	0
Total property and equipment, net	0	0
Goodwill	0	0
Other assets	(128,161)	(234,316)
Total assets	(2,668,199)	(2,719,364)
Accounts payable	(32,042)	(67,344)
Accrued liabilities	(42,511)	(20,823)
Current deferred taxes	0	0
Short Term Borrowings And Current Maturities Of Long Term Debt	0	0
Total current liabilities	(74,553)	(88,167)
Long-term debt, less current maturities	0	0
Intercompany notes payable	(1,336,374)	(1,353,957)
Accrued pension liabilities	0	0
Other liabilities and deferred credits	(140,268)	(159,892)
Deferred taxes	0	0
Common stock	(27,914)	(27,824)
Additional paid-in capital	(271,483)	(258,657)
Retained earnings	(705,915)	(678,655)
Accumulated other comprehensive income (loss)	(111,692)	(152,212)
Treasury shares	0	0
Stockholders' equity	(1,117,004)	(1,117,348)
Noncontrolling interests	0	0
Total stockholders' investment	(1,117,004)	(1,117,348)
Total liabilities and stockholders' investment	$ (2,668,199)	$ (2,719,364)