SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CF (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 36,413	$ 55,412
Capital expenditures	(179,532)	(86,555)
Proceeds from asset dispositions	1,893	20,227
Investment in unconsolidated affiliate	0	(850)
Net cash used in investing activities	(177,639)	(67,178)
Proceeds from borrowings	103,357	0
Debt issuance costs	(12,733)	0
Repayment of debt and debt redemption premiums	(1,733)	(21,800)
Dividends paid	(9,045)	(7,145)
Increases (decreases) in cash related to intercompany advances and debt	0	0
Partial prepayment of put/call obligation	(14)	(17)
Issuance of Common Stock	3,004	311
Tax benefit related to stock-based compensation	2,522	404
Net cash provided by (used in) financing activities	85,358	(28,247)
Effect of exchange rate changes on cash and cash equivalents	237	5,713
Net increase (decrease) in cash and cash equivalents	(55,631)	(34,300)
Cash and cash equivalents at beginning of period	215,623	261,550
Cash and cash equivalents at end of period	159,992	227,250
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(11,746)	(10,350)
Capital expenditures	(5,283)	(445)
Proceeds from asset dispositions	0	0
Investment in unconsolidated affiliate		(850)
Net cash used in investing activities	(5,283)	(1,295)
Proceeds from borrowings	102,000
Debt issuance costs	(12,733)
Repayment of debt and debt redemption premiums	(1,153)	(21,800)
Dividends paid	(9,045)	4,410
Increases (decreases) in cash related to intercompany advances and debt	(98,544)	5,884
Partial prepayment of put/call obligation	(14)	(17)
Issuance of Common Stock	3,004	311
Tax benefit related to stock-based compensation	2,522	404
Net cash provided by (used in) financing activities	(13,963)	(10,808)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(30,992)	(22,453)
Cash and cash equivalents at beginning of period	31,853	76,609
Cash and cash equivalents at end of period	861	54,156
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	33,434	58,170
Capital expenditures	(168,239)	(35,698)
Proceeds from asset dispositions	1,893	9,621
Investment in unconsolidated affiliate		0
Net cash used in investing activities	(166,346)	(26,077)
Proceeds from borrowings	0
Debt issuance costs	0
Repayment of debt and debt redemption premiums	0	0
Dividends paid	0	(9,755)
Increases (decreases) in cash related to intercompany advances and debt	130,801	(21,432)
Partial prepayment of put/call obligation	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	130,801	(31,187)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(2,111)	906
Cash and cash equivalents at beginning of period	5,370	3,155
Cash and cash equivalents at end of period	3,259	4,061
Consolidations, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0
Capital expenditures	0	0
Proceeds from asset dispositions	0	0
Investment in unconsolidated affiliate		0
Net cash used in investing activities	0	0
Proceeds from borrowings	0
Debt issuance costs	0
Repayment of debt and debt redemption premiums	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
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	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	14,725	7,592
Capital expenditures	(6,010)	(50,412)
Proceeds from asset dispositions	0	10,606
Investment in unconsolidated affiliate		0
Net cash used in investing activities	(6,010)	(39,806)
Proceeds from borrowings	1,357
Debt issuance costs	0
Repayment of debt and debt redemption premiums	(580)	0
Dividends paid	0	(1,800)
Increases (decreases) in cash related to intercompany advances and debt	(32,257)	15,548
Partial prepayment of put/call obligation	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	(31,480)	13,748
Effect of exchange rate changes on cash and cash equivalents	237	5,713
Net increase (decrease) in cash and cash equivalents	(22,528)	(12,753)
Cash and cash equivalents at beginning of period	178,400	181,786
Cash and cash equivalents at end of period	$ 155,872	$ 169,033