SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION BS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011
Balance Sheet [Line Items]
Cash and cash equivalents	$ 227,250	$ 261,550	$ 117,070	$ 116,361
Accounts receivable	291,959	286,220
Inventories	157,543	157,825
Assets held for sale	18,100	18,710
Prepaid expenses and other current assets	12,239	12,168
Total current assets	707,091	736,473
Intercompany investment	0	0
Investment in unconsolidated affiliates	201,042	205,100
Intercompany notes receivable	0	0
Land and buildings	81,816	80,835
Aircraft and equipment	2,143,073	2,099,642
Total property and equipment, at cost	2,224,889	2,180,477
Less - Accumulated depreciation and amortization	(467,887)	(457,702)
Total property and equipment, net	1,757,002	1,722,775
Goodwill	29,339	29,644
Other assets	45,905	46,371
Total assets	2,740,379	2,740,363
Accounts payable	57,876	56,084
Accrued liabilities	123,039	113,676
Current deferred taxes	14,963	15,070
Short Term Borrowings And Current Maturities Of Long Term Debt	16,562	14,375
Total current liabilities	212,440	199,205
Long-term debt, less current maturities	719,737	742,870
Intercompany notes payable	0	0
Accrued pension liabilities	109,792	111,742
Other liabilities and deferred credits	14,823	16,768
Deferred taxes	142,388	147,954
Common stock	363	363
Additional paid-in capital	705,984	703,628
Retained earnings	1,009,952	993,435
Accumulated other comprehensive income (loss)	(158,934)	(159,239)
Treasury shares	25,085	25,085
Stockholders' equity	1,532,280	1,513,102
Noncontrolling interests	8,919	8,722
Total stockholders' investment	1,541,199	1,521,824
Total liabilities and stockholders' investment	2,740,379	2,740,363
Parent Company [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	54,156	76,609	57,623	24,075
Accounts receivable	15,671	12,884
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	1,182	1,512
Total current assets	71,009	91,005
Intercompany investment	1,029,404	1,031,041
Investment in unconsolidated affiliates	3,228	2,378
Intercompany notes receivable	1,296,062	1,266,714
Land and buildings	801	801
Aircraft and equipment	14,267	13,969
Total property and equipment, at cost	15,068	14,770
Less - Accumulated depreciation and amortization	(7,751)	(6,705)
Total property and equipment, net	7,317	8,065
Goodwill	0	0
Other assets	110,883	111,442
Total assets	2,517,903	2,510,645
Accounts payable	3,951	3,130
Accrued liabilities	12,452	11,506
Current deferred taxes	(1,218)	(1,571)
Short Term Borrowings And Current Maturities Of Long Term Debt	16,562	14,375
Total current liabilities	31,747	27,440
Long-term debt, less current maturities	719,737	742,870
Intercompany notes payable	0	0
Accrued pension liabilities	0	0
Other liabilities and deferred credits	5,986	6,738
Deferred taxes	126,705	121,385
Common stock	363	363
Additional paid-in capital	705,984	703,628
Retained earnings	1,009,952	993,435
Accumulated other comprehensive income (loss)	(59,033)	(61,706)
Treasury shares	25,085	25,085
Stockholders' equity	1,632,181	1,610,635
Noncontrolling interests	1,547	1,577
Total stockholders' investment	1,633,728	1,612,212
Total liabilities and stockholders' investment	2,517,903	2,510,645
Guarantor Subsidiaries [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	4,061	3,155	4,843	5,233
Accounts receivable	85,616	97,732
Inventories	57,248	57,957
Assets held for sale	1,547	1,400
Prepaid expenses and other current assets	(187)	2,220
Total current assets	148,285	162,464
Intercompany investment	111,434	111,434
Investment in unconsolidated affiliates	150	150
Intercompany notes receivable	0	0
Land and buildings	48,872	48,855
Aircraft and equipment	875,832	880,643
Total property and equipment, at cost	924,704	929,498
Less - Accumulated depreciation and amortization	(190,943)	(186,876)
Total property and equipment, net	733,761	742,622
Goodwill	4,755	4,755
Other assets	2,418	2,416
Total assets	1,000,803	1,023,841
Accounts payable	17,586	26,384
Accrued liabilities	20,429	20,987
Current deferred taxes	(133)	(128)
Short Term Borrowings And Current Maturities Of Long Term Debt	0	0
Total current liabilities	37,882	47,243
Long-term debt, less current maturities	0	0
Intercompany notes payable	273,467	296,335
Accrued pension liabilities	0	0
Other liabilities and deferred credits	8,496	8,754
Deferred taxes	9,105	8,903
Common stock	4,996	4,996
Additional paid-in capital	9,290	9,290
Retained earnings	657,567	648,320
Accumulated other comprehensive income (loss)	0	0
Treasury shares	0	0
Stockholders' equity	671,853	662,606
Noncontrolling interests	0	0
Total stockholders' investment	671,853	662,606
Total liabilities and stockholders' investment	1,000,803	1,023,841
Non-Guarantor Subsidiaries [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	169,033	181,786	54,604	87,053
Accounts receivable	239,553	246,297
Inventories	100,295	99,868
Assets held for sale	16,553	17,310
Prepaid expenses and other current assets	18,560	27,394
Total current assets	543,994	572,655
Intercompany investment	0	0
Investment in unconsolidated affiliates	197,664	202,572
Intercompany notes receivable	(30,775)	(13,792)
Land and buildings	32,143	31,179
Aircraft and equipment	1,252,974	1,205,030
Total property and equipment, at cost	1,285,117	1,236,209
Less - Accumulated depreciation and amortization	(269,193)	(264,121)
Total property and equipment, net	1,015,924	972,088
Goodwill	24,584	24,889
Other assets	166,881	166,829
Total assets	1,918,272	1,925,241
Accounts payable	80,006	93,914
Accrued liabilities	101,338	102,006
Current deferred taxes	16,314	16,769
Short Term Borrowings And Current Maturities Of Long Term Debt	0	0
Total current liabilities	197,658	212,689
Long-term debt, less current maturities	0	0
Intercompany notes payable	1,092,844	1,057,622
Accrued pension liabilities	109,792	111,742
Other liabilities and deferred credits	160,921	161,168
Deferred taxes	6,578	17,666
Common stock	22,881	22,828
Additional paid-in capital	243,520	249,367
Retained earnings	27,272	30,335
Accumulated other comprehensive income (loss)	49,434	54,679
Treasury shares	0	0
Stockholders' equity	343,107	357,209
Noncontrolling interests	7,372	7,145
Total stockholders' investment	350,479	364,354
Total liabilities and stockholders' investment	1,918,272	1,925,241
Consolidations, Eliminations [Member]
Balance Sheet [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable	(48,881)	(70,693)
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	(7,316)	(18,958)
Total current assets	(56,197)	(89,651)
Intercompany investment	(1,140,838)	(1,142,475)
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	(1,265,287)	(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	(234,277)	(234,316)
Total assets	(2,696,599)	(2,719,364)
Accounts payable	(43,667)	(67,344)
Accrued liabilities	(11,180)	(20,823)
Current deferred taxes	0	0
Short Term Borrowings And Current Maturities Of Long Term Debt	0	0
Total current liabilities	(54,847)	(88,167)
Long-term debt, less current maturities	0	0
Intercompany notes payable	(1,366,311)	(1,353,957)
Accrued pension liabilities	0	0
Other liabilities and deferred credits	(160,580)	(159,892)
Deferred taxes	0	0
Common stock	(27,877)	(27,824)
Additional paid-in capital	(252,810)	(258,657)
Retained earnings	(684,839)	(678,655)
Accumulated other comprehensive income (loss)	(149,335)	(152,212)
Treasury shares	0	0
Stockholders' equity	(1,114,861)	(1,117,348)
Noncontrolling interests	0	0
Total stockholders' investment	(1,114,861)	(1,117,348)
Total liabilities and stockholders' investment	$ (2,696,599)	$ (2,719,364)