SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CF (Details) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities			$ 162,410,000	$ 137,299,000
Capital expenditures	(197,166,000)	(186,489,000)	(499,285,000)	(526,048,000)
Proceeds from asset dispositions	6,717,000	89,264,000	404,361,000	244,867,000
Proceeds from sale of unconsolidated affiliate			4,185,000	112,210,000
Net cash used in investing activities			(90,739,000)	(168,971,000)
Proceeds from borrowings			347,860,000	283,977,000
Debt issuance costs			0	(15,152,000)
Repayment of debt			(373,169,000)	(232,063,000)
Dividends paid			(33,935,000)	(27,318,000)
Increases (decreases) in cash related to intercompany advances and debt			0	0
Partial prepayment of put/call obligation			(46,000)	(42,000)
Acquisition of noncontrolling interest			(3,170,000)	(2,078,000)
Proceeds from assignment of aircraft purchase agreements			0	106,113,000
Repurchase of Common Stock	(37,400,000)		(80,831,000)	(16,544,000)
Issuance of Common Stock			2,217,000	14,368,000
Tax benefit related to stock-based compensation			1,642,000	5,328,000
Net cash provided by (used in) financing activities			(139,432,000)	116,589,000
Effect of exchange rate changes on cash and cash equivalents			(15,214,000)	22,690,000
Net increase (decrease) in cash and cash equivalents			(82,975,000)	107,607,000
Cash and cash equivalents at beginning of period			204,341,000	215,623,000
Cash and cash equivalents at end of period	121,366,000	323,230,000	121,366,000	323,230,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities			(88,788,000)	(71,505,000)
Capital expenditures			(38,303,000)	(20,579,000)
Proceeds from asset dispositions			0	0
Proceeds from sale of unconsolidated affiliate			0	0
Net cash used in investing activities			(38,303,000)	(20,579,000)
Proceeds from borrowings			346,500,000	281,100,000
Debt issuance costs				(15,152,000)
Repayment of debt			(363,872,000)	(229,059,000)
Dividends paid			(33,935,000)	(24,252,000)
Increases (decreases) in cash related to intercompany advances and debt			255,878,000	58,519,000
Partial prepayment of put/call obligation			(46,000)	(42,000)
Acquisition of noncontrolling interest			0	0
Proceeds from assignment of aircraft purchase agreements				0
Repurchase of Common Stock			(80,831,000)	(16,544,000)
Issuance of Common Stock			2,217,000	14,368,000
Tax benefit related to stock-based compensation			1,642,000	5,328,000
Net cash provided by (used in) financing activities			127,553,000	74,266,000
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			462,000	(17,818,000)
Cash and cash equivalents at beginning of period			4,640,000	31,853,000
Cash and cash equivalents at end of period	5,102,000	14,035,000	5,102,000	14,035,000
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities			263,933,000	95,359,000
Capital expenditures			(303,951,000)	(411,557,000)
Proceeds from asset dispositions			209,523,000	211,655,000
Proceeds from sale of unconsolidated affiliate			0	0
Net cash used in investing activities			(94,428,000)	(199,902,000)
Proceeds from borrowings			0	0
Debt issuance costs				0
Repayment of debt			0	0
Dividends paid			0	34,000
Increases (decreases) in cash related to intercompany advances and debt			(169,111,000)	3,188,000
Partial prepayment of put/call obligation			0	0
Acquisition of noncontrolling interest			0	0
Proceeds from assignment of aircraft purchase agreements				106,113,000
Repurchase of Common Stock			0	0
Issuance of Common Stock			0	0
Tax benefit related to stock-based compensation			0	0
Net cash provided by (used in) financing activities			(169,111,000)	109,335,000
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			394,000	4,792,000
Cash and cash equivalents at beginning of period			0	5,370,000
Cash and cash equivalents at end of period	394,000	10,162,000	394,000	10,162,000
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities			(13,181,000)	113,445,000
Capital expenditures			(157,031,000)	(199,775,000)
Proceeds from asset dispositions			194,838,000	139,075,000
Proceeds from sale of unconsolidated affiliate			4,185,000	112,210,000
Net cash used in investing activities			41,992,000	51,510,000
Proceeds from borrowings			1,360,000	2,877,000
Debt issuance costs				0
Repayment of debt			(9,297,000)	(3,004,000)
Dividends paid			0	(3,100,000)
Increases (decreases) in cash related to intercompany advances and debt			(86,767,000)	(61,707,000)
Partial prepayment of put/call obligation			0	0
Acquisition of noncontrolling interest			(3,170,000)	(2,078,000)
Proceeds from assignment of aircraft purchase agreements				0
Repurchase of Common Stock			0	0
Issuance of Common Stock			0	0
Tax benefit related to stock-based compensation			0	0
Net cash provided by (used in) financing activities			(97,874,000)	(67,012,000)
Effect of exchange rate changes on cash and cash equivalents			(15,214,000)	22,690,000
Net increase (decrease) in cash and cash equivalents			(84,277,000)	120,633,000
Cash and cash equivalents at beginning of period			200,147,000	178,400,000
Cash and cash equivalents at end of period	115,870,000	299,033,000	115,870,000	299,033,000
Consolidations, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities			446,000	0
Capital expenditures			0	105,863,000
Proceeds from asset dispositions			0	(105,863,000)
Proceeds from sale of unconsolidated affiliate			0	0
Net cash used in investing activities			0	0
Proceeds from borrowings			0	0
Debt issuance costs				0
Repayment of debt			0	0
Dividends paid			0	0
Increases (decreases) in cash related to intercompany advances and debt			0	0
Partial prepayment of put/call obligation			0	0
Acquisition of noncontrolling interest			0	0
Proceeds from assignment of aircraft purchase agreements				0
Repurchase of Common Stock			0	0
Issuance of Common Stock			0	0
Tax benefit related to stock-based compensation			0	0
Net cash provided by (used in) financing activities			0	0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			446,000	0
Cash and cash equivalents at beginning of period			(446,000)	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0	$ 0