XML 17 R1.htm IDEA: XBRL DOCUMENT v3.21.2
Document And Entity Information - USD ($)
12 Months Ended
Sep. 30, 2021
Dec. 06, 2021
Mar. 31, 2021
Document Information [Line Items]      
Entity Central Index Key 0001547459    
Entity Registrant Name Natural Grocers by Vitamin Cottage, Inc.    
Amendment Flag false    
Current Fiscal Year End Date --09-30    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2021    
Document Type 10-K    
Document Annual Report true    
Document Period End Date Sep. 30, 2021    
Document Transition Report false    
Entity File Number 001-35608    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 45-5034161    
Entity Address, Address Line One 12612 West Alameda Parkway    
Entity Address, City or Town Lakewood    
Entity Address, State or Province CO    
Entity Address, Postal Zip Code 80228    
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 Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 169,112,362
Entity Common Stock, Shares Outstanding   22,643,890  
ICFR Auditor Attestation Flag true