Note 1 - Summary of Significant Accounting Policies - Composition of Utility Plant (Details) - USD ($)	Sep. 30, 2024	Sep. 30, 2023
Distribution and transmission	$ 312,999,348	$ 286,200,652
LNG storage	15,437,447	15,407,053
General and miscellaneous	17,427,213	16,762,186
Total utility property in service	$ 345,864,008	$ 318,369,891

Period end amount of other property, plant and equipment (PPE) owned (but not classified elsewhere) by the public utility.

No definition available.

Name:	rgco_PublicUtilitiesPropertyPlantAndEquipmentOtherPropertyPlantAndEquipmentGross
Namespace Prefix:	rgco_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant