Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 28, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2015
Entity Registrant Name	NATIONAL INSTRUMENTS CORP /DE/
Entity Central Index Key	0000935494
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		128,859,698