SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CF (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Sep. 30, 2011	Sep. 30, 2010
Cash Flow [Line Items]
Net cash provided by (used in) operating activities			$ 116,993	$ 69,184
Capital expenditures			(149,262)	(63,943)
Deposits on assets held for sale			0	1,000
Proceeds from sale of joint ventures			0	1,291
Proceeds from asset dispositions			12,040	17,178
Net cash used in investing activities			(137,222)	(44,474)
Proceeds from borrowings			88,493	10,012
Repayment of debt			(32,518)	(7,630)
Dividends paid	(5,400)	(5,400)
Distributions to noncontrolling interest owners			0	(637)
Increases (decreases) in cash related to intercompany advances and debt			0	0
Partial Prepayment Of Put Call Obligation			(31)	(28)
Acquisition of noncontrolling interest			(262)	(800)
Issuance of Common Stock			1,629	111
Tax benefit related to stock-based compensation			109	179
Net cash provided by (used in) financing activities			46,587	1,207
Effect of exchange rate changes on cash and cash equivalents			(2,440)	4,791
Net increase (decrease) in cash and cash equivalents			23,918	30,708
Cash and cash equivalents at beginning of period		116,361	116,361	77,793
Cash and cash equivalents at end of period	140,279		140,279	108,501
Parent Company [Member]
Cash Flow [Line Items]
Net cash provided by (used in) operating activities			(18,520)	(23,393)
Capital expenditures			(418)	(1,696)
Deposits on assets held for sale				0
Proceeds from sale of joint ventures				0
Proceeds from asset dispositions			0	0
Net cash used in investing activities			(418)	(1,696)
Proceeds from borrowings			87,800	0
Repayment of debt			(30,000)	0
Dividends paid			40,564	13,030
Distributions to noncontrolling interest owners				0
Increases (decreases) in cash related to intercompany advances and debt			(22,056)	8,835
Partial Prepayment Of Put Call Obligation			(31)	(28)
Acquisition of noncontrolling interest			0	0
Issuance of Common Stock			1,629	111
Tax benefit related to stock-based compensation			109	179
Net cash provided by (used in) financing activities			78,015	22,127
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			59,077	(2,962)
Cash and cash equivalents at beginning of period		24,075	24,075	16,555
Cash and cash equivalents at end of period	83,152		83,152	13,593
Guarantor Subsidiaries [Member]
Cash Flow [Line Items]
Net cash provided by (used in) operating activities			60,830	25,304
Capital expenditures			(78,620)	(30,957)
Deposits on assets held for sale				1,000
Proceeds from sale of joint ventures				0
Proceeds from asset dispositions			8,129	11,280
Net cash used in investing activities			(70,491)	(18,677)
Proceeds from borrowings			0	8,049
Repayment of debt			0	0
Dividends paid			(24,927)	(11,500)
Distributions to noncontrolling interest owners				0
Increases (decreases) in cash related to intercompany advances and debt			32,153	(5,010)
Partial Prepayment Of Put Call Obligation			0	0
Acquisition of noncontrolling interest			(262)	0
Issuance of Common Stock			0	0
Tax benefit related to stock-based compensation			0	0
Net cash provided by (used in) financing activities			6,964	(8,461)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase (decrease) in cash and cash equivalents			(2,697)	(1,834)
Cash and cash equivalents at beginning of period		5,233	5,233	1,834
Cash and cash equivalents at end of period	2,536		2,536	0
Non-Guarantor Subsidiaries [Member]
Cash Flow [Line Items]
Net cash provided by (used in) operating activities			74,683	68,550
Capital expenditures			(70,224)	(31,290)
Deposits on assets held for sale				0
Proceeds from sale of joint ventures				1,291
Proceeds from asset dispositions			3,911	5,898
Net cash used in investing activities			(66,313)	(24,101)
Proceeds from borrowings			693	1,963
Repayment of debt			(2,518)	(7,630)
Dividends paid			(26,470)	(1,530)
Distributions to noncontrolling interest owners				(637)
Increases (decreases) in cash related to intercompany advances and debt			(10,097)	(3,825)
Partial Prepayment Of Put Call Obligation			0	0
Acquisition of noncontrolling interest			0	(800)
Issuance of Common Stock			0	0
Tax benefit related to stock-based compensation			0	0
Net cash provided by (used in) financing activities			(38,392)	(12,459)
Effect of exchange rate changes on cash and cash equivalents			(2,440)	4,791
Net increase (decrease) in cash and cash equivalents			(32,462)	36,781
Cash and cash equivalents at beginning of period		87,053	87,053	59,404
Cash and cash equivalents at end of period	54,591		54,591	96,185
Consolidations, Eliminations [Member]
Cash Flow [Line Items]
Net cash provided by (used in) operating activities			0	(1,277)
Capital expenditures			0	0
Deposits on assets held for sale				0
Proceeds from sale of joint ventures				0
Proceeds from asset dispositions			0	0
Net cash used in investing activities			0	0
Proceeds from borrowings			0	0
Repayment of debt			0	0
Dividends paid			0	0
Distributions to noncontrolling interest owners				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
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	(1,277)
Cash and cash equivalents at beginning of period		0	0	0
Cash and cash equivalents at end of period	$ 0		$ 0	$ (1,277)