Document And Entity Information - shares	6 Months Ended
	Mar. 31, 2022	May 02, 2022
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	Q2
Document Fiscal Year Focus	2022
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
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, 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	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		22,676,827