Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 365,935	$ 142,554	$ 81,817
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	510,526	257,313	220,835
Deferred income taxes	11,218	48,073	8,276
Excess tax benefit from stock-based compensation	(1,555)	(9,004)	(560)
Gain loss from Equity method investment	(17,880)
Reduction in value of assets		46,096	32,004
Stock based and performance share unit compensation expense	36,570	14,032	33,602
Retirement and deferred compensation plan expense	1,607	1,990	4,825
(Earnings) losses from consolidated subsidiaries
(Earnings) losses from equity-method investments, net of cash received	3,360	(13,152)	2,905
Amortization of debt acquisition costs and note discount	9,856	25,178	23,954
(Gain) loss sale of business	6,649	(8,558)	(1,083)
Writeoff of debt acquisition costs and note discount	3,460
Other reconciling items, net	1,205	(6,426)	(4,708)
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(42,946)	(86,814)	(89,800)
Inventory and other current assets	62,720	2,182	85,687
Accounts payable	(30,977)	40,289	20,303
Accrued expenses	(26,107)	24,961	8,359
Decommissioning liabilities	(4,660)	(504)	(1,759)
Income taxes	152,093	(1,378)	10,510
Other, net	(6,031)	15,972	20,806
Net Cash Provided by (Used in) Operating Activities, Total	1,035,043	492,804	455,973
Cash flows from investing activities:
Payments for capital expenditures	(1,141,922)	(484,648)	(323,244)
Proceeds from Sale of Available-for-sale Securities, Equity	41,874
Change in restricted cash held for acquisition of business	785,280	(785,280)
Acquisitions of businesses, net of cash acquired	(1,091,161)	(1,748)	(276,077)
Cash proceeds from sale of businesses	183,094	22,349	5,250
Proceeds from Sale of Equity Method Investments	34,087
Purchase of short-term investments, net.		(223,491)
Proceeds from sale of short-term investments		223,630
Other	31,630	(721)	(9,402)
Net Cash Provided by (Used in) Investing Activities, Total	(1,157,118)	(1,249,909)	(603,473)
Cash flows from financing activities:
Repayments of Long-term Lines of Credit	(771,439)	(424,913)	(577,867)
Proceeds from Long-term Lines of Credit	696,439	324,913	575,867
Proceeds from issuance of long-term debt	400,000	1,300,000
Principal payments of long-term debt	(177,546)	(400,810)	(810)
Payment of debt acquisition costs	(25,274)	(24,428)	(5,182)
Proceeds from exercise of stock options	14,777	10,263	927
Excess tax benefit from stock-based compensation	1,555	9,004	560
Proceeds from issuance of stock through employee benefit plans	2,855	2,206	1,891
Other	(10,383)	(9,662)	(3,443)
Net Cash Provided by (Used in) Financing Activities, Total	130,984	786,573	(8,057)
Effect of exchange rate changes on cash	2,016	79	(221)
Net increase in cash and cash equivalents	10,925	29,547	(155,778)
Cash and cash equivalents at beginning of period	80,274	50,727	206,505
Cash and cash equivalents at end of period	$ 91,199	$ 80,274	$ 50,727