Discontinued Operations (Details) (USD $)
 3 Months Ended 12 Months Ended 9 Months Ended 3 Months Ended
Sep. 30, 2014
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Sep. 30, 2014
Dec. 31, 2014
Aug. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                  
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax       $ 33,885,000 $ 0 $ 0      
Asset Impairment Charges 47,900,000 38,200,000 85,300,000     22,800,000      
CHILE                  
ASSETS                  
Cash and cash equivalents         3,448,000        
Accounts receivable, net of allowance for doubtful accounts of $6,762         11,157,000        
Handset and accessory inventory         5,965,000        
Prepaid expenses and other         38,526,000        
Property, plant and equipment, net         50,515,000        
Intangible assets, net         13,300,000        
Other assets         46,020,000        
Total assets         168,931,000        
LIABILITIES                  
Accounts payable         22,928,000        
Accrued expenses and other         13,841,000        
Other long-term liabilities         5,326,000        
Total liabilities         42,095,000        
Allowance for doubtful accounts         6,762,000        
Nextel Peru [Member]                  
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                  
Disposal group, sale price                 405,500,000
Disposal group, sale price, escrow deposit                 50,000,000
Gain (loss) on disposal of Nextel Chile and Nextel Peru       (29,585,000) 2,848,000 0      
Operating revenues       38,596,000 265,979,000 393,227,000      
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]                  
Operating revenues       38,596,000 265,979,000 393,227,000      
Operating expenses       (228,578,000) (443,166,000) (1,010,229,000)      
Other expense, net       (19,989,000) (34,576,000) (2,443,000)      
Loss before income tax provision       (209,971,000) (211,763,000) (619,445,000)      
Income tax provision       0 (900,000) (63,965,000)      
Loss from discontinued operations, before loss on disposal, net of income taxes       (209,971,000) (212,663,000) (683,410,000)      
Gain (loss) on disposal of Nextel Chile and Nextel Peru       (29,585,000) 2,848,000 0      
Loss from discontinued operations, net of income taxes       (180,386,000) (215,511,000) (683,410,000)      
Release Of Consideration       2,000,000     7,500,000    
CHILE                  
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                  
Asset Impairment Charges               127,500,000  
Gain (loss) on disposal of Nextel Chile and Nextel Peru       (32,700,000)          
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]                  
Gain (loss) on disposal of Nextel Chile and Nextel Peru       (32,700,000)          
ASSETS                  
Total assets         $ 168,900,000