Document and Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2016	Aug. 26, 2016	Dec. 31, 2015
Entity Information [Line Items]
Entity Registrant Name	Delta Natural Gas Co Inc
Entity Central Index Key	0000277375
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 148,491,236
Entity Common Stock, Shares Outstanding		7,088,586
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2016