Condensed Consolidating Financial Statements (Narrative) (Details) (USD $)
12 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Aug. 31, 2009
Dec. 31, 2009
Mar. 31, 2011
Dec. 31, 2011
Net Cash Provided by (Used in) Investing Activities $ (347,538,000) $ (177,612,000) $ (1,055,160,000)        
Net cash (used in) provided by operating activities (628,716,000) (192,451,000) 353,183,000        
Net Cash Provided by (Used in) Financing Activities (128,272,000) 776,591,000 (238,295,000)        
NII Holdings Inc. (Parent) [Member]              
Net Cash Provided by (Used in) Investing Activities (153,556,000) (206,031,000) (94,619,000)        
Net cash (used in) provided by operating activities (95,925,000) (171,667,000) 3,293,000        
Net Cash Provided by (Used in) Financing Activities (86,000) (1,010,000) (216,010,000)        
Guarantor Subsidiaries [Member]              
Net Cash Provided by (Used in) Investing Activities 25,378,000 (15,492,000) (92,574,000)        
Net cash (used in) provided by operating activities (152,715,000) (159,744,000) (108,934,000)        
Net Cash Provided by (Used in) Financing Activities 136,256,000 174,353,000 199,561,000        
7.875% Senior Notes Due 2019 [Member]              
Notes interest rate 7.875%            
7.625% Senior Notes Due 2021 [Member]              
Principal amount 1,450,000,000            
Notes interest rate           7.625%  
10.0% and 8.875% Senior Notes Due 2019 and 2016 [Member]              
Senior Notes $ 1,300,000,000            
10.0% Senior Notes Due 2016 [Member]              
Notes interest rate       10.00%      
Maturity Date       August 15, 2016      
8.875% Senior Notes Due 2019 [Member]              
Notes interest rate             8.875%
Maturity Date         December 15, 2019