v3.8.0.1
Document - $ / shares
9 Months Ended
Sep. 30, 2017
Oct. 20, 2017
Document Information [Line Items]    
Entity Registrant Name FIRST SOLAR, INC.  
Entity Central Index Key 0001274494  
Document Type 10-Q  
Document Period End Date Sep. 30, 2017  
Amendment Flag false  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Par Value Per Share $ 0.001  
Entity Common Stock Shares Outstanding   104,432,988