v3.26.1
Summary of significant accounting policies (Details)
6 Months Ended
Mar. 31, 2026
Properties [Member]  
Property, Plant, and Equipment [Line Items]  
Property plant and equipmment useful life 30 years
Automobiles [Member]  
Property, Plant, and Equipment [Line Items]  
Property plant and equipmment useful life 10 years
Leasehold Improvements [Member]  
Property, Plant, and Equipment [Line Items]  
Property plant and equipmment useful life Over shorter of the lease term and the remining useful life