Supplemental Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash provided by (used in) 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
Contributions from parent
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
Transactions with affiliates, net
Cash provided by (used in) financing activities	(44,564)	469,689
Increase (decrease) 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
Parent/Issuer [Member]
Cash provided by (used in) operating activities	(22,206)	(610,129)
Investing Activities
Capital expenditures	(2,488)	(4,150)
Minimum royalty payments
Proceeds from dispositions of property, plant and equipment
Proceeds from sale-leaseback transactions
Proceeds from sale of Canyon Fuel
Purchases of short term investments	(85,418)	(99,628)
Proceeds from sales of short term investments	67,255
Investments in and advances to affiliates	(4,016)	(5,138)
Purchase of noncontrolling interest
Change in restricted cash	3,453	6,872
Cash provided by (used in) investing activities	(21,214)	(102,044)
Financing Activities
Contributions from parent
Proceeds from issuance of term loan		1,386,000
Payments on term loan	(12,375)	(3,500)
Payments to retire debt
Net decrease in borrowings under lines of credit		(375,000)
Net payments on other debt	(12,700)	(13,078)
Debt financing costs		(34,640)
Dividends paid	(19,105)	(36,072)
Proceeds from exercise of options under incentive plans		5,131
Transactions with affiliates, net	437,532	30,338
Cash provided by (used in) financing activities	393,352	959,179
Increase (decrease) in cash and cash equivalents	349,932	247,006
Cash and cash equivalents, beginning of period	671,313	66,542
Cash and cash equivalents, end of period	1,021,245	313,548
Guarantor Subsidiaries [Member]
Cash provided by (used in) operating activities	153,868	874,545
Investing Activities
Capital expenditures	(220,680)	(299,818)
Minimum royalty payments	(10,901)	(9,192)
Proceeds from dispositions of property, plant and equipment	8,799	1,127
Proceeds from sale-leaseback transactions	34,919
Proceeds from sale of Canyon Fuel	422,663
Purchases of short term investments
Proceeds from sales of short term investments
Investments in and advances to affiliates	(7,492)	(9,082)
Purchase of noncontrolling interest		(17,500)
Change in restricted cash
Cash provided by (used in) investing activities	227,308	(334,465)
Financing Activities
Contributions from parent	384	1,535
Proceeds from issuance of term loan
Payments on term loan
Payments to retire debt	(384)	(452,806)
Net decrease in borrowings under lines of credit
Net payments on other debt
Debt financing costs
Dividends paid
Proceeds from exercise of options under incentive plans
Transactions with affiliates, net	(381,234)	66,364
Cash provided by (used in) financing activities	(381,234)	(384,907)
Increase (decrease) in cash and cash equivalents	(58)	155,173
Cash and cash equivalents, beginning of period	100,468	70,258
Cash and cash equivalents, end of period	100,410	225,431
Non-Guarantor Subsidiaries [Member]
Cash provided by (used in) operating activities	54,930	91,979
Investing Activities
Capital expenditures
Minimum royalty payments
Proceeds from dispositions of property, plant and equipment		21,497
Proceeds from sale-leaseback transactions
Proceeds from sale of Canyon Fuel
Purchases of short term investments
Proceeds from sales of short term investments
Investments in and advances to affiliates
Purchase of noncontrolling interest
Change in restricted cash
Cash provided by (used in) investing activities		21,497
Financing Activities
Contributions from parent
Proceeds from issuance of term loan
Payments on term loan
Payments to retire debt
Net decrease in borrowings under lines of credit		(6,300)
Net payments on other debt
Debt financing costs		(46)
Dividends paid
Proceeds from exercise of options under incentive plans
Transactions with affiliates, net	(56,298)	(96,702)
Cash provided by (used in) financing activities	(56,298)	(103,048)
Increase (decrease) in cash and cash equivalents	(1,368)	10,428
Cash and cash equivalents, beginning of period	12,841	1,349
Cash and cash equivalents, end of period	11,473	11,777
Eliminations [Member]
Cash provided by (used in) operating activities
Investing Activities
Capital expenditures
Minimum royalty payments
Proceeds from dispositions of property, plant and equipment
Proceeds from sale-leaseback transactions
Proceeds from sale of Canyon Fuel
Purchases of short term investments
Proceeds from sales of short term investments
Investments in and advances to affiliates	384	1,535
Purchase of noncontrolling interest
Change in restricted cash
Cash provided by (used in) investing activities	384	1,535
Financing Activities
Contributions from parent	(384)	(1,535)
Proceeds from issuance of term loan
Payments on term loan
Payments to retire debt
Net decrease in borrowings under lines of credit
Net payments on other debt
Debt financing costs
Dividends paid
Proceeds from exercise of options under incentive plans
Transactions with affiliates, net
Cash provided by (used in) financing activities	(384)	(1,535)
Increase (decrease) in cash and cash equivalents
Cash and cash equivalents, beginning of period
Cash and cash equivalents, end of period