Supplemental Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Cash Flows) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Condensed Financial Statements, Captions [Line Items]    
Cash provided by (used in) operating activities $ (4,273) $ (40,275)
Investing Activities    
Capital expenditures (22,880) (14,454)
Additions to prepaid royalties (213) (591)
Proceeds from disposals and divestitures 46 28,195
Purchases of marketable securities (101,793) (119,176)
Proceeds from sales of short term investments 99,914 117,681
Investments in and advances to affiliates (1,843) (3,242)
Cash provided by (used in) investing activities (26,769) 8,413
Financing Activities    
Payments on term loan (4,875) (4,875)
Debt financing costs   (1,957)
Net payments on other debt (4,810) (4,521)
Dividends paid 0 (2,123)
Withdrawals (deposits) of restricted cash (3,532) 0
Cash used in financing activities (13,217) (13,476)
Increase (decrease) in cash and cash equivalents (44,259) (45,338)
Cash and cash equivalents, beginning of period 734,231 911,099
Cash and cash equivalents, end of period 689,972 865,761
Parent/Issuer [Member]    
Condensed Financial Statements, Captions [Line Items]    
Cash provided by (used in) operating activities (114,542) (150,338)
Investing Activities    
Capital expenditures (450) (492)
Additions to prepaid royalties   0
Proceeds from disposals and divestitures   26,319
Purchases of marketable securities (101,793) (119,176)
Proceeds from sales of short term investments 99,914 117,681
Investments in and advances to affiliates   (1,016)
Cash provided by (used in) investing activities (2,329) 23,316
Financing Activities    
Contributions from parent   0
Payments on term loan (4,875) (4,875)
Debt financing costs   (1,957)
Net payments on other debt (2,751) (4,521)
Dividends paid   (2,123)
Withdrawals (deposits) of restricted cash 0  
Transactions with affiliates, net 130,144 95,067
Cash used in financing activities 122,518 81,591
Increase (decrease) in cash and cash equivalents 5,647 (45,431)
Cash and cash equivalents, beginning of period 572,185 799,333
Cash and cash equivalents, end of period 577,832 753,902
Guarantor Subsidiaries [Member]    
Condensed Financial Statements, Captions [Line Items]    
Cash provided by (used in) operating activities 96,944 142,978
Investing Activities    
Capital expenditures (22,430) (13,962)
Additions to prepaid royalties (213) (591)
Proceeds from disposals and divestitures 46 1,876
Purchases of marketable securities   0
Proceeds from sales of short term investments   0
Investments in and advances to affiliates (1,843) (2,226)
Cash provided by (used in) investing activities (24,440) (14,903)
Financing Activities    
Payments on term loan 0 0
Net payments on other debt (2,059)  
Dividends paid   0
Withdrawals (deposits) of restricted cash 0  
Transactions with affiliates, net (120,373) (128,140)
Cash used in financing activities (122,432) (128,140)
Increase (decrease) in cash and cash equivalents (49,928) (65)
Cash and cash equivalents, beginning of period 150,358 100,418
Cash and cash equivalents, end of period 100,430 100,353
Non-Guarantor Subsidiaries [Member]    
Condensed Financial Statements, Captions [Line Items]    
Cash provided by (used in) operating activities 13,325 (32,915)
Investing Activities    
Capital expenditures   0
Additions to prepaid royalties   0
Proceeds from disposals and divestitures   0
Purchases of marketable securities   0
Proceeds from sales of short term investments   0
Financing Activities    
Contributions from parent   0
Payments on term loan 0 0
Debt financing costs   0
Net payments on other debt   0
Dividends paid   0
Withdrawals (deposits) of restricted cash (3,532)  
Transactions with affiliates, net (9,771) 33,073
Cash used in financing activities (13,303) 33,073
Increase (decrease) in cash and cash equivalents 22 158
Cash and cash equivalents, beginning of period 11,688 11,348
Cash and cash equivalents, end of period 11,710 11,506
Eliminations [Member]    
Condensed Financial Statements, Captions [Line Items]    
Cash provided by (used in) operating activities   0
Investing Activities    
Capital expenditures   0
Additions to prepaid royalties   0
Proceeds from disposals and divestitures   0
Purchases of marketable securities   0
Proceeds from sales of short term investments   0
Financing Activities    
Payments on term loan 0  
Withdrawals (deposits) of restricted cash 0  
Transactions with affiliates, net   0
Increase (decrease) in cash and cash equivalents   0
Cash and cash equivalents, beginning of period 0 0
Cash and cash equivalents, end of period $ 0 $ 0