CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 88,707,000	$ 187,779,000	$ 131,675,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	114,293,000	95,977,000	96,284,000
Deferred income tax	(7,457,000)	5,465,000	(8,587,000)
Write-off of deferred financing fees	660,000	12,733,000	4,642,000
Discount amortization on long-term debt	4,323,000	3,708,000	3,597,000
(Gain) loss on disposal of assets	35,849,000	722,000	(8,068,000)
Gain on sale of unconsolidated affiliates	3,921,000	103,924,000	0
Impairment of inventories	7,167,000	12,669,000	0
Extinguishment of debt	2,591,000	0	14,932,000
Stock-based compensation	16,353,000	15,433,000	11,869,000
Equity in earnings from unconsolidated affiliates less than (in excess of) dividends received	9,418,000	1,629,000	(9,244,000)
Tax benefit related to stock-based compensation	(1,550,000)	(5,723,000)	(500,000)
Increase (decrease) in cash resulting from changes in:
Accounts receivable	24,112,000	3,647,000	(2,739,000)
Inventories	(21,478,000)	12,824,000	(1,340,000)
Prepaid expenses and other assets	(25,485,000)	(3,149,000)	(39,269,000)
Accounts payable	(4,665,000)	(5,154,000)	25,654,000
Accrued liabilities	29,461,000	11,697,000	38,790,000
Other liabilities and deferred credits	(15,152,000)	(14,239,000)	9,068,000
Net cash provided by operating activities	253,226,000	232,094,000	266,764,000
Cash flows from investing activities:
Capital expenditures	(601,834,000)	(628,613,000)	(571,425,000)
Acquisitions, net of cash received	(20,303,000)	(39,850,000)	0
Proceeds from sale of unconsolidated affiliates	4,185,000	112,210,000	0
Proceeds from asset dispositions	414,859,000	289,951,000	314,847,000
Investment in unconsolidated affiliate	0	0	(51,179,000)
Net cash used in investing activities	(203,093,000)	(266,302,000)	(307,757,000)
Cash flows from financing activities:
Proceeds from borrowings	454,393,000	533,064,000	675,449,000
Payments of contingent consideration	0	(6,000,000)	0
Debt issuance costs	0	(15,523,000)	(10,344,000)
Repayment of debt and debt redemption premiums	(460,274,000)	(512,492,000)	(663,921,000)
Proceeds from assignment of aircraft purchase agreements	0	106,113,000	0
Partial prepayment of put/call obligation	(59,000)	(57,000)	(63,000)
Acquisition of noncontrolling interest	(3,170,000)	(2,078,000)	0
Repurchase of common stock	(80,831,000)	(77,661,000)	(1,219,000)
Common stock dividends paid	(45,078,000)	(36,320,000)	(28,734,000)
Issuance of common stock	5,172,000	15,398,000	15,289,000
Tax benefit related to stock-based compensation	1,550,000	5,723,000	500,000
Net cash provided by (used in) financing activities	(128,297,000)	10,167,000	(13,043,000)
Effect of exchange rate changes on cash and cash equivalents	(22,031,000)	12,759,000	8,109,000
Net increase (decrease) in cash and cash equivalents	(100,195,000)	(11,282,000)	(45,927,000)
Cash and cash equivalents at beginning of period	204,341,000	215,623,000	261,550,000
Cash and cash equivalents at end of period	104,146,000	204,341,000	215,623,000
Supplemental disclosure of cash flow information:
Aircraft received for payment on accounts receivable	0	0	8,300,000
Contingent liability for investment in unconsolidated affiliate	0	0	34,245,000
Deferred sale leaseback advance	69,680,000	60,194,000	0
Completion of deferred sale leaseback	(183,688,000)	0	0
Aircraft sold for future spare parts and maintenance	$ 13,417	$ 0	$ 0