Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activties
Net income (loss)	$ (270,618)	$ (388,264)
Adjustments to reconcile net loss to cash provided by operating activities:
Depreciation, depletion and amortization	348,863	399,672
Amortization of acquired sales contracts, net	(7,587)	(22,561)
Amortization relating to financing activities	18,525	14,345
Prepaid royalties expensed	11,973	19,802
Employee stock-based compensation expense	8,909	9,435
Asset impairment and noncash mine closure costs	220,879	501,942
Amortization of premiums on debt securities held	3,679
Gain on sale of Canyon Fuel	(115,679)
Goodwill impairment		115,791
Net loss resulting from early retirement of debt and financing activities		19,042
Changes in:
Receivables	72,436	102,252
Inventories	21,387	(16,635)
Coal derivative assets and liabilities	(1,568)	(29,523)
Accounts payable, accrued expenses and other current liabilities	19,287	(51,968)
Income taxes, net	787	22,048
Deferred income taxes	184,418	255,530
Other	39,737	(83,453)
Cash provided by operating activities	186,592	356,395
Investing activities
Capital expenditures	(223,168)	(303,968)
Minimum royalty payments	(10,901)	(9,192)
Proceeds from dispositions of property, plant and equipment	8,799	22,624
Proceeds from sale-leaseback transactions	34,919
Proceeds from sale of Canyon Fuel	422,663
Purchases of short term investments	(85,418)	(99,628)
Proceeds from sales of short term investments	67,255
Investments in and advances to affiliates	(11,124)	(12,685)
Purchase of noncontrolling interest		(17,500)
Change in restricted cash	3,453	6,872
Cash provided by (used in) investing activities	206,478	(413,477)
Financing activities
Proceeds from issuance of term loan		1,386,000
Payments on term loan	(12,375)	(3,500)
Payments to retire debt	(384)	(452,806)
Net decrease in borrowings under lines of credit		(381,300)
Net payments on other debt	(12,700)	(13,078)
Debt financing costs		(34,686)
Dividends paid	(19,105)	(36,072)
Proceeds from exercise of options under incentive plans		5,131
Cash provided by (used in) financing activities	(44,564)	469,689
Increase in cash and cash equivalents	348,506	412,607
Cash and cash equivalents, beginning of period	784,622	138,149
Cash and cash equivalents, end of period	$ 1,133,128	$ 550,756