v3.26.1
Document And Entity Information - shares
 9 Months Ended
Jun. 30, 2026
Aug. 03, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Transition Report false  
Entity File Number 001-35608  
Entity Registrant Name Natural Grocers by Vitamin Cottage, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 45-5034161  
Entity Address, Address Line One 12612 West Alameda Parkway  
Entity Address, Postal Zip Code 80228  
Entity Address, City or Town Lakewood  
Entity Address, State or Province CO  
City Area Code 303  
Local Phone Number 986-4600  
Title of 12(b) Security Common Stock, $0.001 par value  
Trading Symbol NGVC  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding (in shares)   23,045,851
Entity Central Index Key 0001547459  
Current Fiscal Year End Date --09-30  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q3  
Amendment Flag false