Selected Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Information (Details) - USD ($)	1 Months Ended		3 Months Ended											12 Months Ended
	Dec. 31, 2016	Dec. 31, 2013	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	[1]	Mar. 31, 2016	Dec. 31, 2015	[2]	Sep. 30, 2015	Mar. 31, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Revenues			$ 8,835,702	$ 9,525,437	$ 8,529,817	$ 7,593,940	$ 7,240,434		$ 5,106,735	$ 6,622,927		$ 7,379,406		$ 34,484,896	$ 26,349,502	$ 27,841,265
Operating income (loss)			2,583,912	3,893,236	3,675,381	2,727,593	954,823		(681,147)	(454,987)		1,846,498		12,880,122	1,665,187	8,583,697
Net income (loss) available to common shareholders			$ 1,500,761	$ 2,419,143	$ 2,307,634	$ 563,345	$ 20,705,894		$ (298,183)	$ 654,697		$ 2,923,652		6,790,883	23,986,060	4,317,555
Basic and diluted net income per share (in dollars per share)			$ 0.05	$ 0.07	$ 0.07	$ 0.02	$ 0.63		$ (0.01)	$ 0.02		$ 0.09
Dividends per share declared and paid in the quarter (in dollars per share)	$ 0.065	$ 0.10	$ 0.07	$ 0.07	$ 0.065	$ 0.05	$ 0.05		$ 0.05	$ 0.05		$ 0.05	$ 0.05
Restructuring charges (income)					$ 1,300,000									4,488	1,257,433	(5,431)
Delhi field litigation settlement gain														0	$ 28,096,500	$ 0
Dehli Field Litigation
Delhi field litigation settlement gain														$ 28,100,000

[1] Includes gain on settlement of Delhi field litigation of $28.1 million.

[2] Includes $1.3 million restructuring charge.