Document and Entity Information	6 Months Ended
	Dec. 31, 2015 USD ($) shares
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 | shares	7,074,380
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2015