Quarterly Financial Data (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Operating Revenues	$ 10,860,988	$ 26,202,462	$ 16,673,347	$ 10,393,423	$ 11,906,360	$ 35,085,307	$ 25,875,266	$ 13,321,305	$ 64,130,220	$ 86,188,238	$ 95,845,871
Operating Income	1,003,794	7,084,268	3,478,479	(132,549)	618,299	7,286,400	4,899,101	160,061	11,433,992	12,963,861	15,603,439
Net income (Loss)	$ 267,043	$ 3,983,441	$ 1,803,351	$ (524,457)	$ (4,464)	$ 4,155,136	$ 2,656,534	$ (311,125)	$ 5,529,378	$ 6,496,081	$ 8,275,128
Basic Earnings (Loss) per Common Share (in dollars per share)	$ 0.05	$ 0.56	$ 0.25	$ (0.08)	$ 0.00	$ 0.59	$ 0.38	$ (0.05)	$ 0.78	$ 0.92	$ 1.19
Diluted Earnings (Loss) per Common Share (in dollars per share)									$ 0.78	$ 0.92	$ 1.19