SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CF (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 37,345	$ 36,413
Capital expenditures	(200,447)	(179,532)
Proceeds from asset dispositions	6,643	1,893
Net cash used in investing activities	(193,804)	(177,639)
Proceeds from borrowings	148,044	103,357
Debt issuance costs	0	(12,733)
Repayment of debt	(35,848)	(1,733)
Dividends paid	(11,353)	(9,045)
Increases (decreases) in cash related to intercompany advances and debt	0	0
Partial prepayment of put/call obligation	(15)	(14)
Acquisition of noncontrolling interest	0
Proceeds from assignment of aircraft purchase agreements	0
Repurchase of Common Stock	(20,157)	0
Issuance of Common Stock	975	3,004
Tax benefit related to stock-based compensation	166	2,522
Net cash provided by (used in) financing activities	81,812	85,358
Effect of exchange rate changes on cash and cash equivalents	4,110	237
Net increase (decrease) in cash and cash equivalents	(70,537)	(55,631)
Cash and cash equivalents at beginning of period	204,341	215,623
Cash and cash equivalents at end of period	133,804	159,992
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(22,755)	(11,746)
Capital expenditures	(11,219)	(5,283)
Proceeds from asset dispositions	0	0
Net cash used in investing activities	(11,219)	(5,283)
Proceeds from borrowings	147,500	102,000
Debt issuance costs	0	(12,733)
Repayment of debt	(31,891)	(1,153)
Dividends paid	(11,353)	(9,045)
Increases (decreases) in cash related to intercompany advances and debt	(49,231)	(98,544)
Partial prepayment of put/call obligation	(15)	(14)
Acquisition of noncontrolling interest	0
Proceeds from assignment of aircraft purchase agreements	0
Repurchase of Common Stock	(20,157)
Issuance of Common Stock	975	3,004
Tax benefit related to stock-based compensation	166	2,522
Net cash provided by (used in) financing activities	35,994	(13,963)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	2,020	(30,992)
Cash and cash equivalents at beginning of period	4,640	31,853
Cash and cash equivalents at end of period	6,660	861
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	54,360	33,434
Capital expenditures	(98,694)	(168,239)
Proceeds from asset dispositions	6,423	1,893
Net cash used in investing activities	(92,271)	(166,346)
Proceeds from borrowings	0	0
Debt issuance costs	0	0
Repayment of debt	0	0
Dividends paid	0	0
Increases (decreases) in cash related to intercompany advances and debt	37,911	130,801
Partial prepayment of put/call obligation	0	0
Acquisition of noncontrolling interest	0
Proceeds from assignment of aircraft purchase agreements	0
Repurchase of Common Stock	0
Issuance of Common Stock	0	0
Tax benefit related to stock-based compensation	0	0
Net cash provided by (used in) financing activities	37,911	130,801
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	0	(2,111)
Cash and cash equivalents at beginning of period	0	5,370
Cash and cash equivalents at end of period	0	3,259
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	7,158	14,725
Capital expenditures	(90,534)	(6,010)
Proceeds from asset dispositions	220	0
Net cash used in investing activities	(90,314)	(6,010)
Proceeds from borrowings	544	1,357
Debt issuance costs	0	0
Repayment of debt	(3,957)	(580)
Dividends paid	0	0
Increases (decreases) in cash related to intercompany advances and debt	11,320	(32,257)
Partial prepayment of put/call obligation	0	0
Acquisition of noncontrolling interest	0
Proceeds from assignment of aircraft purchase agreements	0
Repurchase of Common Stock	0
Issuance of Common Stock	0	0
Tax benefit related to stock-based compensation	0	0
Net cash provided by (used in) financing activities	7,907	(31,480)
Effect of exchange rate changes on cash and cash equivalents	4,110	237
Net increase (decrease) in cash and cash equivalents	(71,139)	(22,528)
Cash and cash equivalents at beginning of period	200,147	178,400
Cash and cash equivalents at end of period	129,008	155,872
Consolidations, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(1,418)	0
Capital expenditures	0	0
Proceeds from asset dispositions	0	0
Net cash used in investing activities	0	0
Proceeds from borrowings	0	0
Debt issuance costs	0	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
Proceeds from assignment of aircraft purchase agreements	0
Repurchase of Common Stock	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	(1,418)	0
Cash and cash equivalents at beginning of period	(446)	0
Cash and cash equivalents at end of period	$ (1,864)	$ 0