Financial Information Related to Guarantor Subsidiaries (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ 53,920	$ 15,503
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	103,841	59,363
Deferred income taxes	(10,979)	2,773
Excess tax benefit from stock-based compensation	(843)	(5,078)
Stock based and performance share unit compensation expense	10,591	3,686
Retirement and deferred compensation plan expense	621	123
(Earnings) losses from equity-method investments, net of cash received	2,921	(27)
Amortization of debt acquisition costs and note discount	2,210	6,255
(Gain) loss sale of business	6,649	(2,674)
Other reconciling items, net	3,481	(1,482)
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(64,163)	78,834
Inventory and other current assets	(15,868)	(3,015)
Accounts payable	28,436	(2,305)
Accrued expenses	(56,346)	(13,145)
Decommissioning liabilities	(2,661)		(2,661)
Income taxes	38,809	(2,558)
Other, net	(6,562)	1,692
Net cash provided by (used in) operating activities	94,057	137,945
Cash flows from investing activities:
Payments for capital expenditures	(273,245)	(108,579)
Acquisitions of businesses, net of cash acquired	(1,038,241)
Change in restricted cash held for acquisition of business	785,280
Cash proceeds from sale of businesses	185,912	5,762
Other	3,305	(1,974)
Net cash provided by (used in) investing activities	(336,989)	(104,791)
Cash flows from financing activities:
Net payments on revolving line of credit	(75,000)	(19,000)
Proceeds from long-term debt	400,000
Principal payments of long-term debt	(12,546)
Payment of debt acquisition costs	(25,011)
Proceeds from exercise of stock options	12,256	6,147
Excess tax benefit from stock-based compensation	843	5,078
Proceeds from issuance of stock through employee benefit plans	819	634
Other	(3,610)	(6,551)
Net cash provided by (used in) financing activities	297,751	(13,692)
Effect of exchange rate changes on cash	665	893
Net increase (decrease) in cash and cash equivalents	55,484	20,355
Cash and cash equivalents at beginning of period	80,274	50,727	71,082
Cash and cash equivalents at end of period	135,758	71,082	135,758
Parent [Member]
Cash flows from operating activities:
Net income (loss)	53,920	15,503
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Deferred income taxes	(12,133)	2,967
Excess tax benefit from stock-based compensation	(843)	(5,078)
(Earnings) losses from consolidated subsidiaries	(87,637)	(23,427)
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accrued expenses	(69)	12
Income taxes	39,080	(2,436)
Other, net	(108)	(46)
Net cash provided by (used in) operating activities	(7,790)	(12,505)
Cash flows from investing activities:
Intercompany receivables/payables	(5,739)	646
Net cash provided by (used in) investing activities	(5,739)	646
Cash flows from financing activities:
Proceeds from exercise of stock options	12,256	6,147
Excess tax benefit from stock-based compensation	843	5,078
Proceeds from issuance of stock through employee benefit plans	819	634
Other	(389)
Net cash provided by (used in) financing activities	13,529	11,859
Issuer [Member]
Cash flows from operating activities:
Net income (loss)	87,637	23,427
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	191	128
Stock based and performance share unit compensation expense	10,591	3,686
Retirement and deferred compensation plan expense	621	123
(Earnings) losses from consolidated subsidiaries	(180,551)	(49,706)
(Earnings) losses from equity-method investments, net of cash received	2,787	878
Amortization of debt acquisition costs and note discount	2,210	6,255
Other reconciling items, net	5,373	(374)
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	179	3,043
Inventory and other current assets	(3)	(17)
Accounts payable	2,076	(219)
Accrued expenses	22,717	(6,365)
Other, net	(3,749)	859
Net cash provided by (used in) operating activities	(49,921)	(24,368)
Cash flows from investing activities:
Payments for capital expenditures	(4,738)
Acquisitions of businesses, net of cash acquired	(1,229,327)
Change in restricted cash held for acquisition of business	785,280
Cash proceeds from sale of businesses	185,912
Intercompany receivables/payables	36,370	66,043
Net cash provided by (used in) investing activities	(226,503)	66,043
Cash flows from financing activities:
Net payments on revolving line of credit	(75,000)	(19,000)
Proceeds from long-term debt	400,000
Payment of debt acquisition costs	(25,011)
Other	(2,365)	(5,830)
Net cash provided by (used in) financing activities	297,624	(24,830)
Net increase (decrease) in cash and cash equivalents	21,200	16,845
Cash and cash equivalents at beginning of period	29,057
Cash and cash equivalents at end of period	50,257	16,845	50,257
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net income (loss)	190,181	61,078
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	87,047	48,691
(Earnings) losses from consolidated subsidiaries	(12,411)	(634)
(Gain) loss sale of business	6,649	(2,674)
Other reconciling items, net	(2,288)	(1,108)
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(63,263)	67,549
Inventory and other current assets	(13,150)	(3,096)
Accounts payable	13,060	1,930
Accrued expenses	(74,489)	(4,670)
Decommissioning liabilities	(2,661)
Other, net	1,903	1,705
Net cash provided by (used in) operating activities	130,578	168,771
Cash flows from investing activities:
Payments for capital expenditures	(238,448)	(78,773)
Acquisitions of businesses, net of cash acquired	106,952
Cash proceeds from sale of businesses		5,762
Other	2,603	(1,974)
Intercompany receivables/payables	23,605	(97,368)
Net cash provided by (used in) investing activities	(105,288)	(172,353)
Cash flows from financing activities:
Net increase (decrease) in cash and cash equivalents	25,290	(3,582)
Cash and cash equivalents at beginning of period	6,272	5,493
Cash and cash equivalents at end of period	31,562	1,911	31,562
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net income (loss)	2,781	(10,738)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	16,603	10,544
Deferred income taxes	1,154	(194)
(Earnings) losses from equity-method investments, net of cash received	134	(905)
Other reconciling items, net	396
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(1,079)	14,328
Inventory and other current assets	(2,715)	98
Accounts payable	13,300	(4,016)
Accrued expenses	(4,505)	(2,122)
Income taxes	(271)	(122)
Other, net	(4,608)	(826)
Net cash provided by (used in) operating activities	21,190	6,047
Cash flows from investing activities:
Payments for capital expenditures	(30,059)	(29,806)
Acquisitions of businesses, net of cash acquired	84,134
Other	702
Intercompany receivables/payables	(54,236)	30,679
Net cash provided by (used in) investing activities	541	873
Cash flows from financing activities:
Principal payments of long-term debt	(12,546)
Other	(856)	(721)
Net cash provided by (used in) financing activities	(13,402)	(721)
Effect of exchange rate changes on cash	665	893
Net increase (decrease) in cash and cash equivalents	8,994	7,092
Cash and cash equivalents at beginning of period	44,945	45,234
Cash and cash equivalents at end of period	53,939	52,326	53,939
Eliminations [Member]
Cash flows from operating activities:
Net income (loss)	(280,599)	(73,767)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
(Earnings) losses from consolidated subsidiaries	$ 280,599	$ 73,767