SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION BS (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 215,623	$ 261,550	$ 116,361	$ 77,793
Accounts receivable	262,781	286,220
Inventories	153,969	157,825
Assets held for sale	8,290	18,710
Prepaid expenses and other current assets	35,095	12,168
Total current assets	675,758	736,473
Intercompany investment	0	0
Investment in unconsolidated affiliates	272,123	205,100
Intercompany notes receivable	0	0
Total property and equipment, at cost	2,414,647	2,180,477
Less - Accumulated depreciation and amortization	(493,575)	(457,702)
Total property and equipment, net	1,921,072	1,722,775
Goodwill	28,897	29,644	32,047
Other assets	52,842	46,371
Total assets	2,950,692	2,740,363
Accounts payable	69,821	56,084
Accrued liabilities	147,681	113,676
Current deferred taxes	0	15,070
Short-term borrowings and current maturities of long-term debt	22,323	14,375
Total current liabilities	239,825	199,205
Long-term debt, less current maturities	764,946	742,870
Intercompany notes payable	0	0
Accrued pension liabilities	126,647	111,742
Other liabilities and deferred credits	57,196	16,768
Deferred taxes	151,121	147,954
Common stock	367	363
Additional paid-in capital	731,883	703,628
Retained earnings	1,094,803	993,435
Accumulated other comprehensive income (loss)	(199,683)	(159,239)
Treasury shares	(26,304)	(25,085)
Stockholders' equity	1,601,066	1,513,102
Noncontrolling interests	9,891	8,722
Total stockholders' investment	1,610,957	1,521,824	1,518,775	1,356,571
Total liabilities and stockholders' investment	2,950,692	2,740,363
Land and Building [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, at cost	108,593	80,835
Aircraft and equipment [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, at cost	2,306,054	2,099,642
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	31,853	76,609	24,075	16,555
Accounts receivable	18,498	12,884
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	16,071	1,512
Total current assets	66,422	91,005
Intercompany investment	1,163,935	1,031,041
Investment in unconsolidated affiliates	0	2,378
Intercompany notes receivable	1,401,680	1,266,714
Total property and equipment, at cost	32,249	14,770
Less - Accumulated depreciation and amortization	(10,680)	(6,705)
Total property and equipment, net	21,569	8,065
Goodwill	0	0
Other assets	40,877	111,442
Total assets	2,694,483	2,510,645
Accounts payable	4,049	3,130
Accrued liabilities	29,534	11,506
Current deferred taxes	(4,184)	(1,571)
Short-term borrowings and current maturities of long-term debt	21,875	14,375
Total current liabilities	51,274	27,440
Long-term debt, less current maturities	764,946	742,870
Intercompany notes payable	0	0
Accrued pension liabilities	0	0
Other liabilities and deferred credits	10,761	6,738
Deferred taxes	128,153	121,385
Common stock	367	363
Additional paid-in capital	731,883	703,628
Retained earnings	1,094,803	993,435
Accumulated other comprehensive income (loss)	(62,892)	(61,706)
Treasury shares	(26,304)	(25,085)
Stockholders' equity	1,737,857	1,610,635
Noncontrolling interests	1,492	1,577
Total stockholders' investment	1,739,349	1,612,212
Total liabilities and stockholders' investment	2,694,483	2,510,645
Parent Company [Member] | Land and Building [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	939	801
Parent Company [Member] | Aircraft and equipment [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	31,310	13,969
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	5,370	3,155	5,233	1,834
Accounts receivable	80,615	97,732
Inventories	51,970	57,957
Assets held for sale	1,268	1,400
Prepaid expenses and other current assets	12,415	2,220
Total current assets	151,638	162,464
Intercompany investment	111,435	111,434
Investment in unconsolidated affiliates	150	150
Intercompany notes receivable	0	0
Total property and equipment, at cost	1,219,438	929,498
Less - Accumulated depreciation and amortization	(205,746)	(186,876)
Total property and equipment, net	1,013,692	742,622
Goodwill	4,756	4,755
Other assets	1,341	2,416
Total assets	1,283,012	1,023,841
Accounts payable	44,017	26,384
Accrued liabilities	22,404	20,987
Current deferred taxes	115	(128)
Short-term borrowings and current maturities of long-term debt	0	0
Total current liabilities	66,536	47,243
Long-term debt, less current maturities	0	0
Intercompany notes payable	463,184	296,335
Accrued pension liabilities	0	0
Other liabilities and deferred credits	8,530	8,754
Deferred taxes	8,328	8,903
Common stock	4,996	4,996
Additional paid-in capital	9,291	9,290
Retained earnings	722,147	648,320
Accumulated other comprehensive income (loss)	0	0
Treasury shares	0	0
Stockholders' equity	736,434	662,606
Noncontrolling interests	0	0
Total stockholders' investment	736,434	662,606
Total liabilities and stockholders' investment	1,283,012	1,023,841
Guarantor Subsidiaries [Member] | Land and Building [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	48,907	48,855
Guarantor Subsidiaries [Member] | Aircraft and equipment [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	1,170,531	880,643
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	178,400	181,786	87,053	59,404
Accounts receivable	246,612	246,297
Inventories	101,999	99,868
Assets held for sale	7,022	17,310
Prepaid expenses and other current assets	23,263	27,394
Total current assets	557,296	572,655
Intercompany investment	0	0
Investment in unconsolidated affiliates	271,973	202,572
Intercompany notes receivable	0	(13,792)
Total property and equipment, at cost	1,162,960	1,236,209
Less - Accumulated depreciation and amortization	(277,149)	(264,121)
Total property and equipment, net	885,811	972,088
Goodwill	24,141	24,889
Other assets	149,544	166,829
Total assets	1,888,765	1,925,241
Accounts payable	101,021	93,914
Accrued liabilities	115,112	102,006
Current deferred taxes	4,069	16,769
Short-term borrowings and current maturities of long-term debt	448	0
Total current liabilities	220,650	212,689
Long-term debt, less current maturities	0	0
Intercompany notes payable	963,687	1,057,622
Accrued pension liabilities	126,647	111,742
Other liabilities and deferred credits	178,525	161,168
Deferred taxes	14,640	17,666
Common stock	22,876	22,828
Additional paid-in capital	270,905	249,367
Retained earnings	62,602	30,335
Accumulated other comprehensive income (loss)	19,834	54,679
Treasury shares	0	0
Stockholders' equity	376,217	357,209
Noncontrolling interests	8,399	7,145
Total stockholders' investment	384,616	364,354
Total liabilities and stockholders' investment	1,888,765	1,925,241
Non-Guarantor Subsidiaries [Member] | Land and Building [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	58,747	31,179
Non-Guarantor Subsidiaries [Member] | Aircraft and equipment [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	1,104,213	1,205,030
Consolidations, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable	(82,944)	(70,693)
Inventories	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	(16,654)	(18,958)
Total current assets	(99,598)	(89,651)
Intercompany investment	(1,275,370)	(1,142,475)
Investment in unconsolidated affiliates	0	0
Intercompany notes receivable	(1,401,680)	(1,252,922)
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	(138,920)	(234,316)
Total assets	(2,915,568)	(2,719,364)
Accounts payable	(79,266)	(67,344)
Accrued liabilities	(19,369)	(20,823)
Current deferred taxes	0	0
Short-term borrowings and current maturities of long-term debt	0	0
Total current liabilities	(98,635)	(88,167)
Long-term debt, less current maturities	0	0
Intercompany notes payable	(1,426,871)	(1,353,957)
Accrued pension liabilities	0	0
Other liabilities and deferred credits	(140,620)	(159,892)
Deferred taxes	0	0
Common stock	(27,872)	(27,824)
Additional paid-in capital	(280,196)	(258,657)
Retained earnings	(784,749)	(678,655)
Accumulated other comprehensive income (loss)	(156,625)	(152,212)
Treasury shares	0	0
Stockholders' equity	(1,249,442)	(1,117,348)
Noncontrolling interests	0	0
Total stockholders' investment	(1,249,442)	(1,117,348)
Total liabilities and stockholders' investment	(2,915,568)	(2,719,364)
Consolidations, Eliminations [Member] | Land and Building [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	0	0
Consolidations, Eliminations [Member] | Aircraft and equipment [Member]
Condensed Financial Statements, Captions [Line Items]
Total property and equipment, net	$ 0	$ 0