Document and Entity Information - USD ($)	9 Months Ended
	Mar. 31, 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	7,082,184
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016