Supplemental Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			$ (60,252)	$ (125,575)
Investing Activities
Capital expenditures	$ (68,211)	$ (76,481)	(74,137)	(99,361)
Additions to prepaid royalties			(217)	(409)
Proceeds from (consideration paid for) disposals and divestitures			(3,303)	991
Purchases of marketable securities			(98,750)	(161,336)
Proceeds from sale or maturity of marketable securities and other investments			94,589	157,729
Investments in and advances to affiliates			(2,890)	(5,138)
Withdrawals (deposits) of restricted cash			(4,695)	(37,885)
Cash used in investing activities			(89,403)	(145,409)
Financing Activities
Payments on term loan			0	(9,750)
Net payments on other debt			(10,293)	(9,826)
Expenses related to proposed debt restructuring			(2,213)	(4,016)
Debt financing costs			(18,806)	0
Transactions with affiliates, net			0	0
Cash used in financing activities			(31,312)	(23,592)
Decrease in cash and cash equivalents			(180,967)	(294,576)
Cash and cash equivalents, beginning of period			450,781	734,231
Cash and cash equivalents, end of period	269,814	439,655	269,814	439,655
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			0	0
Investing Activities
Capital expenditures			0	0
Additions to prepaid royalties			0	0
Proceeds from (consideration paid for) disposals and divestitures			0	0
Purchases of marketable securities			0	0
Proceeds from sale or maturity of marketable securities and other investments			0	0
Investments in and advances to affiliates			0	0
Withdrawals (deposits) of restricted cash			0	0
Cash used in investing activities			0	0
Financing Activities
Payments on term loan				0
Net payments on other debt			0	0
Expenses related to proposed debt restructuring			0	0
Debt financing costs			0
Transactions with affiliates, net			0	0
Cash used in financing activities			0	0
Decrease in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	0	0	0	0
Parent/Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			(102,998)	(295,792)
Investing Activities
Capital expenditures			(26)	(815)
Additions to prepaid royalties			0	0
Proceeds from (consideration paid for) disposals and divestitures			0	0
Purchases of marketable securities			(98,750)	(161,336)
Proceeds from sale or maturity of marketable securities and other investments			94,589	157,729
Investments in and advances to affiliates				(788)
Withdrawals (deposits) of restricted cash			0	0
Cash used in investing activities			(4,187)	(5,210)
Financing Activities
Payments on term loan				(9,750)
Net payments on other debt			(4,372)	(5,973)
Expenses related to proposed debt restructuring			(2,213)	(4,016)
Debt financing costs			(15,625)
Transactions with affiliates, net			(319)	116,224
Cash used in financing activities			(22,529)	96,485
Decrease in cash and cash equivalents			(129,714)	(204,517)
Cash and cash equivalents, beginning of period			337,646	572,185
Cash and cash equivalents, end of period	207,932	367,668	207,932	367,668
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			56,656	163,345
Investing Activities
Capital expenditures			(74,111)	(98,546)
Additions to prepaid royalties			(217)	(409)
Proceeds from (consideration paid for) disposals and divestitures			(3,303)	991
Purchases of marketable securities			0	0
Proceeds from sale or maturity of marketable securities and other investments			0	0
Investments in and advances to affiliates			(2,890)	(4,350)
Withdrawals (deposits) of restricted cash			0	0
Cash used in investing activities			(80,521)	(102,314)
Financing Activities
Payments on term loan				0
Net payments on other debt			(5,921)	(3,853)
Expenses related to proposed debt restructuring			0	0
Debt financing costs			0
Transactions with affiliates, net			(20,216)	(146,968)
Cash used in financing activities			(26,137)	(150,821)
Decrease in cash and cash equivalents			(50,002)	(89,790)
Cash and cash equivalents, beginning of period			100,428	150,358
Cash and cash equivalents, end of period	50,426	60,568	50,426	60,568
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			(13,910)	6,872
Investing Activities
Capital expenditures			0	0
Additions to prepaid royalties			0	0
Proceeds from (consideration paid for) disposals and divestitures			0	0
Purchases of marketable securities			0	0
Proceeds from sale or maturity of marketable securities and other investments			0	0
Investments in and advances to affiliates			0	0
Withdrawals (deposits) of restricted cash			(4,695)	(37,885)
Cash used in investing activities			(4,695)	(37,885)
Financing Activities
Payments on term loan				0
Net payments on other debt			0	0
Expenses related to proposed debt restructuring			0	0
Debt financing costs			(3,181)
Transactions with affiliates, net			20,535	30,744
Cash used in financing activities			17,354	30,744
Decrease in cash and cash equivalents			(1,251)	(269)
Cash and cash equivalents, beginning of period			12,707	11,688
Cash and cash equivalents, end of period	$ 11,456	$ 11,419	$ 11,456	$ 11,419