Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Cash Flows From Operating Activities
Net income	$ 5,529,378	$ 6,496,081	$ 8,275,128
Adjustments to reconcile net income to net cash from operating activities
Depreciation and amortization	6,649,721	6,617,743	6,420,525
Deferred income taxes and investment tax credits	1,193,793	1,449,471	(515,492)
Change in cash surrender value of officer's life insurance	6,198	(19,036)	(67,722)
Share-based compensation	452,230	1,095,051	1,111,966
Excess Tax deficiency from share-based Compensation	(7,581)	(9,574)	(8,967)
(Increase) decrease in assets
Accounts receivable	1,091,517	871,270	2,216,925
Natural gas in storage	1,344,242	2,491,337	(1,644,186)
Deferred natural gas cost	(674,077)	724,923	3,197,921
Materials and supplies	(4,549)	(12,578)	(288,597)
Prepayments	(1,226,279)	(363,263)	(1,253,798)
Other assets	(288,867)	225,771	11,556
Increase (decrease) in liabilities
Accounts payable	(1,181,356)	(1,135,821)	169,226
Accrued taxes	106,856	(80,925)	83,528
Asset retirement obligations	(85,068)	375,073	(553,612)
Other liabilities	1,832,112	20,658	185,805
Net cash provided by operating activities	14,738,270	18,746,181	17,340,206
Cash Flows From Investing Activities
Capital expenditures	(6,302,666)	(9,010,876)	(8,077,642)
Proceeds from sale of property, plant and equipment	275,397	161,311	268,082
Other	(60,000)	(60,000)	(60,000)
Net cash used in investing activities	(6,087,269)	(8,909,565)	(7,869,560)
Cash Flows From Financing Activities
Dividends on common shares	(5,822,259)	(5,639,791)	(5,289,911)
Dividends	5,822,259	5,639,791	5,289,911
Issuance of common shares	614,518	532,712	595,249
Excess Tax Benefit from Share-based Compensation	2,073	18,823	39,472
Payment of minimum tax withholding	(263,044)	0	0
Repayment of long-term debt	(1,500,000)	(1,500,000)	(1,500,000)
Borrowings on bank line of credit	0	126,430	691,157
Repayment of bank line of credit	0	(126,430)	(691,157)
Net cash used in financing activities	(6,968,712)	(6,588,256)	(6,155,190)
Net Increase in Cash and Cash Equivalents	1,682,289	3,248,360	3,315,456
Cash and Cash Equivalents, Beginning of Year	16,924,278	13,675,918	10,360,462
Cash and Cash Equivalents, End of Year	18,606,567	16,924,278	13,675,918
Cash paid during the year for
Interest	2,298,228	2,369,078	2,436,435
Income taxes (net of refunds)	2,064,005	3,312,944	5,819,956
Significant non-cash transactions
Accrued capital expenditures	$ 157,808	$ 207,169	$ 328,638