Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities:
Net income	$ 56,515	$ 35,790
Loss from discontinued operations, net of tax	(77)	(100)
Income from continuing operations	56,592	35,890
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	93,561	85,380
Earnings, net of distributions, from equity method investments	1,277	1,181
Deferred income taxes	44,663	32,596
Changes in current assets and liabilities, net of acquisitions:
Receivables	32,206	101,917
Inventories	(19,126)	(38,357)
Other current assets	(25,855)	(21,556)
Accounts payable	(35,091)	(29,851)
Other current liabilities	(7,338)	(33,751)
Other noncurrent changes	(4,318)	(8,349)
Net cash provided by continuing operations	136,571	125,100
Net cash provided by (used in) discontinued operations	303	(107)
Net cash provided by operating activities	136,874	124,993
Investing activities:
Capital expenditures	(188,475)	(174,429)
Acquisitions, net of cash acquired	0	(242)
Net proceeds from sale or disposition of property and other	18,176	18,256
Investments	(514)	(27)
Net cash used in continuing operations	(170,813)	(156,442)
Net cash provided by discontinued operations	0	0
Net cash used in investing activities	(170,813)	(156,442)
Financing activities:
Issuance of short-term borrowings	9,300	0
Issuance of long-term debt	112,015	0
Repayment of long-term debt	(67,123)	(8,297)
Proceeds from issuance of common stock	0	88
Dividends paid	(171)	(31,794)
Excess tax benefit on stock-based compensation	0	26
Contribution from noncontrolling interest	5,000	0
Net cash provided by (used in) continuing operations	59,021	(39,977)
Net cash provided by discontinued operations	0	0
Net cash provided by (used in) financing activities	59,021	(39,977)
Effect of exchange rate changes on cash and cash equivalents	25	43
Increase (decrease) in cash and cash equivalents	25,107	(71,383)
Cash and cash equivalents - beginning of year	49,042	162,772
Cash and cash equivalents - end of year	$ 74,149	$ 91,389