v3.26.1
Note 7 - Long-Term Debt - Long-term Debt (Details) - USD ($)
Jun. 30, 2026
Sep. 30, 2025
Notes payable $ 135,985,662 $ 137,104,215
Unamortized debt issuance costs 344,437 405,794
Revolving credit facility 12,811,880  
Less: current maturities of long-term debt (2,846,018) (2,846,018)
Total long-term debt, net current maturities 133,139,644 134,258,197
Roanoke Gas Company [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Senior Notes Payable, at 4.26%, Due on September 18, 2034 [Member]    
Notes payable 30,500,000 30,500,000
Unamortized debt issuance costs 79,646 86,887
Roanoke Gas Company [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Term Notes Payable, at 3.58%, Due on October 2, 2027 [Member]    
Notes payable 8,000,000 8,000,000
Unamortized debt issuance costs 6,020 9,632
Roanoke Gas Company [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Term Notes Payable, at 4.41 %, Due on March 28, 2031 [Member]    
Notes payable 10,000,000 10,000,000
Unamortized debt issuance costs 14,880 17,229
Roanoke Gas Company [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Term Notes Payable, at 3.60%, Due on December 6, 2029 [Member]    
Notes payable 10,000,000 10,000,000
Unamortized debt issuance costs 12,330 14,971
Roanoke Gas Company [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Term Notes Payable, at 30-day SOFR Average 1.20% Due August 20, 2026 [Member]    
Notes payable 15,000,000 15,000,000
Unamortized debt issuance costs 0 0
Roanoke Gas Company [Member] | Unsecured Senior Notes Payable [Member] | Unsecured term note payable, at Term SOFR plus 1.00%, due October 1, 2028 [Member]    
Notes payable 10,000,000 10,000,000
Unamortized debt issuance costs 15,972 22,612
Roanoke Gas Company [Member] | Unsecured Delayed-draw Term Note Payable [Member] | Unsecured Delayed-draw Term Note Payable at Term SOFR Plus 1.00%, Due August 20, 2029 [Member]    
Notes payable 0  
Unamortized debt issuance costs 20,908  
RGC Midstream LLC [Member] | Southgate Revolving Credit Facility [Member] | Revolving Credit Facility [Member]    
Unamortized debt issuance costs 4,706 5,553
Revolving credit facility 405,233 4,215
RGC Midstream LLC [Member] | Boost Revolving Credit Facility [Member] | Revolving Credit Facility [Member]    
Unamortized debt issuance costs 9,285 10,956
Revolving credit facility 614,942 0
RGC Midstream LLC [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Term Note Payable at Term SOFR Plus 1.55%, Due September 5, 2032 [Member]    
Notes payable 37,062,832 38,600,000
Unamortized debt issuance costs 130,124 171,362
RGC Midstream LLC [Member] | Unsecured Senior Notes Payable [Member] | Unsecured Term Note Payable at Term SOFR Plus 1.55%, Due September 5, 2032 2 [Member]    
Notes payable 14,402,655 15,000,000
Unamortized debt issuance costs $ 50,566 $ 66,592