v3.26.1
Note 8 - Property and Equipment - Depreciation and Amortization Expense 2 (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Depreciation and amortization expense $ 8,332 $ 7,953 $ 24,456 $ 23,791
Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense        
Depreciation and amortization expense 966 827 2,769 2,091
Location, Statement of Income, Balance [Axis]: ngvc:CostOfGoodsSoldAndOccupancyCosts        
Depreciation and amortization expense 216 207 653 603
Location, Statement of Income, Balance [Axis]: ngvc:PreOpeningCostsAndRelocationExpenses        
Depreciation and amortization expense 22 10 130 10
Location, Statement of Income, Balance [Axis]: ngvc:StoreExpenses        
Depreciation and amortization expense $ 7,128 $ 6,909 $ 20,904 $ 21,087