v3.19.3
Cover - shares
9 Months Ended
Sep. 30, 2019
Oct. 29, 2019
Cover page.    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2019  
Document Transition Report false  
Entity File Number 0-25426  
Entity Registrant Name NATIONAL INSTRUMENTS CORP  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 74-1871327  
Entity Address, Address Line One 11500 North MoPac Expressway   
Entity Address, City or Town Austin,  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 78759  
City Area Code 512  
Local Phone Number 683-0100  
Trading Symbol NATI  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Title of 12(b) Security Common Stock, $0.01 par value  
Entity Common Stock, Shares Outstanding   131,059,097
Entity Central Index Key 0000935494  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Amendment Flag false