Supplemental Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			$ (31,234)	$ (79,682)
Investing Activities
Capital expenditures	$ (8,296)	$ (9,889)	(82,434)	(109,250)
Additions to prepaid royalties			(305)	(5,808)
Proceeds from (consideration paid for) disposals and divestitures			(2,921)	1,020
Purchases of marketable securities			(98,750)	(203,094)
Proceeds from sale or maturity of marketable securities and other investments			187,006	248,362
Investments in and advances to affiliates			(3,440)	(7,944)
Change in restricted cash			15,979	(44,732)
Cash provided by (used in) investing activities			15,135	(121,446)
Financing Activities
Payments on term loan			0	(14,625)
Net payments on other debt			(12,083)	(12,192)
Expenses related to proposed debt restructuring			(2,213)	(11,498)
Debt financing costs			(20,181)	0
Transactions with affiliates, net			0	0
Cash used in financing activities			(34,477)	(38,315)
Decrease in cash and cash equivalents			(50,576)	(239,443)
Cash and cash equivalents, beginning of period			450,781	734,231
Cash and cash equivalents, end of period	400,205	494,788	400,205	494,788
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
Change in restricted cash			0	0
Cash provided by (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			(186,456)	(353,386)
Investing Activities
Capital expenditures			(166)	(956)
Additions to prepaid royalties			0	0
Proceeds from (consideration paid for) disposals and divestitures			0	0
Purchases of marketable securities			(98,750)	(203,094)
Proceeds from sale or maturity of marketable securities and other investments			187,006	248,362
Investments in and advances to affiliates				(788)
Change in restricted cash			0	0
Cash provided by (used in) investing activities			88,090	43,524
Financing Activities
Payments on term loan				(14,625)
Net payments on other debt			(4,430)	(5,814)
Expenses related to proposed debt restructuring			(2,213)	(11,498)
Debt financing costs			(17,000)
Transactions with affiliates, net			172,701	132,257
Cash used in financing activities			149,058	100,320
Decrease in cash and cash equivalents			50,692	(209,542)
Cash and cash equivalents, beginning of period			337,646	572,185
Cash and cash equivalents, end of period	388,338	362,643	388,338	362,643
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			198,137	279,503
Investing Activities
Capital expenditures			(82,268)	(108,294)
Additions to prepaid royalties			(305)	(5,808)
Proceeds from (consideration paid for) disposals and divestitures			(2,921)	1,020
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			(3,440)	(7,156)
Change in restricted cash			0	0
Cash provided by (used in) investing activities			(88,934)	(120,238)
Financing Activities
Payments on term loan				0
Net payments on other debt			(7,653)	(6,378)
Expenses related to proposed debt restructuring			0	0
Debt financing costs			0
Transactions with affiliates, net			(201,558)	(182,761)
Cash used in financing activities			(209,211)	(189,139)
Decrease in cash and cash equivalents			(100,008)	(29,874)
Cash and cash equivalents, beginning of period			100,428	150,358
Cash and cash equivalents, end of period	420	120,484	420	120,484
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash provided by (used in) operating activities			(42,915)	(5,799)
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
Change in restricted cash			15,979	(44,732)
Cash provided by (used in) investing activities			15,979	(44,732)
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			28,857	50,504
Cash used in financing activities			25,676	50,504
Decrease in cash and cash equivalents			(1,260)	(27)
Cash and cash equivalents, beginning of period			12,707	11,688
Cash and cash equivalents, end of period	$ 11,447	$ 11,661	$ 11,447	$ 11,661