Cover - shares	6 Months Ended
	Jun. 30, 2020	Jul. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
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		131,436,108
Entity Central Index Key	0000935494
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false