SELECTED CONSOLIDATING FINANCIAL STATEMENTS OF PARENT, GUARANTORS AND NON-GUARANTORS (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Mar. 31, 2012
Current assets:
Cash and cash equivalents	$ 22,443	$ 32,037	$ 30,651	$ 29,662
Trade and other receivables, net	434,860	433,984
Inventories	1,095,502	987,899
Rotable assets	38,172	34,853
Deferred income taxes	51,140	99,546
Prepaid expenses and other	20,072	23,593
Assets Held-for-sale, Current	0	14,747
Total current assets	1,662,189	1,626,659
Property and equipment, net	898,631	815,084
Goodwill and other intangible assets, net	2,683,187	2,675,759
Other, net	68,267	66,792
Intercompany investments and advances	0	0
Total assets	5,312,274	5,184,294
Current liabilities:
Current portion of long-term debt	48,894	133,930
Accounts payable	290,188	327,426
Accrued expenses	264,546	276,668
Liabilities of Assets Held-for-sale	0	2,621
Total current liabilities	603,628	740,645
Long-term debt, less current portion	1,399,398	1,195,933
Intercompany debt	0	0
Accrued pension and other postretirement benefits, noncurrent	597,709	671,175
Deferred income taxes and other	524,424	531,383
Total stockholders' equity	2,187,115	2,045,158
Total liabilities and stockholders' equity	5,312,274	5,184,294
Parent
Current assets:
Cash and cash equivalents	3,120	3,110	3,483	7,969
Trade and other receivables, net	1,264	1,141
Inventories	0	0
Rotable assets	0	0
Deferred income taxes	51,129	0
Prepaid expenses and other	5,152	5,533
Assets Held-for-sale, Current		0
Total current assets	60,665	9,784
Property and equipment, net	10,567	9,999
Goodwill and other intangible assets, net	0	335
Other, net	56,885	58,526
Intercompany investments and advances	3,339,235	3,137,667
Total assets	3,467,352	3,216,311
Current liabilities:
Current portion of long-term debt	32,360	109,648
Accounts payable	0	9,400
Accrued expenses	47,400	35,894
Liabilities of Assets Held-for-sale		0
Total current liabilities	79,760	154,942
Long-term debt, less current portion	1,184,969	998,200
Intercompany debt	0	0
Accrued pension and other postretirement benefits, noncurrent	7,376	7,264
Deferred income taxes and other	8,132	10,747
Total stockholders' equity	2,187,115	2,045,158
Total liabilities and stockholders' equity	3,467,352	3,216,311
Guarantors Subsidiaries
Current assets:
Cash and cash equivalents	818	1,537	514	2,237
Trade and other receivables, net	194,246	171,186
Inventories	1,046,062	957,077
Rotable assets	24,619	24,903
Deferred income taxes	0	99,546
Prepaid expenses and other	10,802	15,170
Assets Held-for-sale, Current		14,747
Total current assets	1,276,547	1,284,166
Property and equipment, net	805,635	753,510
Goodwill and other intangible assets, net	2,604,946	2,629,908
Other, net	8,865	7,873
Intercompany investments and advances	96,691	325,786
Total assets	4,792,684	5,001,243
Current liabilities:
Current portion of long-term debt	16,534	24,282
Accounts payable	273,032	309,363
Accrued expenses	193,874	231,260
Liabilities of Assets Held-for-sale		2,621
Total current liabilities	483,440	567,526
Long-term debt, less current portion	54,129	47,733
Intercompany debt	2,052,759	2,193,874
Accrued pension and other postretirement benefits, noncurrent	590,333	663,911
Deferred income taxes and other	511,728	521,885
Total stockholders' equity	1,100,295	1,006,314
Total liabilities and stockholders' equity	4,792,684	5,001,243
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	18,505	27,390	26,654	19,456
Trade and other receivables, net	239,350	261,657
Inventories	49,440	30,822
Rotable assets	13,553	9,950
Deferred income taxes	11	0
Prepaid expenses and other	4,118	2,890
Assets Held-for-sale, Current		0
Total current assets	324,977	332,709
Property and equipment, net	82,429	51,575
Goodwill and other intangible assets, net	78,241	45,516
Other, net	2,517	393
Intercompany investments and advances	5,369	2,777
Total assets	493,533	432,970
Current liabilities:
Current portion of long-term debt	0	0
Accounts payable	17,156	8,663
Accrued expenses	23,272	9,514
Liabilities of Assets Held-for-sale		0
Total current liabilities	40,428	18,177
Long-term debt, less current portion	160,300	150,000
Intercompany debt	179,085	202,621
Accrued pension and other postretirement benefits, noncurrent	0	0
Deferred income taxes and other	16,845	0
Total stockholders' equity	96,875	62,172
Total liabilities and stockholders' equity	493,533	432,970
Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Trade and other receivables, net	0	0
Inventories	0	0
Rotable assets	0	0
Deferred income taxes	0	0
Prepaid expenses and other	0	0
Assets Held-for-sale, Current		0
Total current assets	0	0
Property and equipment, net	0	0
Goodwill and other intangible assets, net	0	0
Other, net	0	0
Intercompany investments and advances	(3,441,295)	(3,466,230)
Total assets	(3,441,295)	(3,466,230)
Current liabilities:
Current portion of long-term debt	0	0
Accounts payable	0	0
Accrued expenses	0	0
Liabilities of Assets Held-for-sale		0
Total current liabilities	0	0
Long-term debt, less current portion	0	0
Intercompany debt	(2,231,844)	(2,396,495)
Accrued pension and other postretirement benefits, noncurrent	0	0
Deferred income taxes and other	(12,281)	(1,249)
Total stockholders' equity	(1,197,170)	(1,068,486)
Total liabilities and stockholders' equity	$ (3,441,295)	$ (3,466,230)