v2.4.0.6
Document and Entity Information
6 Months Ended
Jun. 30, 2013
Jul. 31, 2013
Class A Common Stock [Member]
Jul. 31, 2013
Class B Convertible Common Stock [Member]
Entity Information [Line Items]      
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Jun. 30, 2013    
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus Q2    
Trading Symbol UA    
Entity Registrant Name UNDER ARMOUR, INC.    
Entity Central Index Key 0001336917    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   85,055,842 20,430,000