Condensed Consolidated Statements of Shareholders' Equity - USD ($)	Common stock	Treasury stock	Additional paid-in capital	Retained earnings	Total
Balance at Mar. 31, 2017	$ 583,422	$ (33,897,269)	$ 852,974,373	$ 156,341,192	$ 976,001,718
Balance (in shares) at Mar. 31, 2017	58,342,201
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period				(6,689,970)	(6,689,970)
Restricted share award issuances	$ 2,685		(2,685)
Restricted share award issuances (in shares)	268,464
Stock-based compensation			1,524,217		1,524,217
Purchase of treasury stock		(1,084,902)			(1,084,902)
Balance at Jun. 30, 2017	$ 586,107	(34,982,171)	854,495,905	149,651,222	969,751,063
Balance (in shares) at Jun. 30, 2017	58,610,665
Balance at Mar. 31, 2017	$ 583,422	(33,897,269)	852,974,373	156,341,192	976,001,718
Balance (in shares) at Mar. 31, 2017	58,342,201
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period					(16,934,691)
Balance at Dec. 31, 2017	$ 586,304	(34,982,171)	856,948,710	139,406,501	961,959,344
Balance (in shares) at Dec. 31, 2017	58,630,441
Balance at Jun. 30, 2017	$ 586,107	(34,982,171)	854,495,905	149,651,222	969,751,063
Balance (in shares) at Jun. 30, 2017	58,610,665
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period				(11,915,136)	(11,915,136)
Restricted share award issuances	$ 100		(100)
Restricted share award issuances (in shares)	10,062
Stock-based compensation			1,175,571		1,175,571
Balance at Sep. 30, 2017	$ 586,207	(34,982,171)	855,671,376	137,736,086	959,011,498
Balance (in shares) at Sep. 30, 2017	58,620,727
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period				1,670,415	1,670,415
Restricted share award issuances	$ 97		(97)
Restricted share award issuances (in shares)	9,714
Stock-based compensation			1,277,431		1,277,431
Balance at Dec. 31, 2017	$ 586,304	(34,982,171)	856,948,710	139,406,501	961,959,344
Balance (in shares) at Dec. 31, 2017	58,630,441
Balance at Mar. 31, 2018	$ 586,402	(35,223,428)	858,109,882	135,940,506	959,413,362
Balance (in shares) at Mar. 31, 2018	58,640,161
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period				(20,596,558)	(20,596,558)
Restricted share award issuances	$ 2,095		(2,095)
Restricted share award issuances (in shares)	209,552
Stock-based compensation			1,632,538		1,632,538
Purchase of treasury stock		(1,133,018)			(1,133,018)
Balance at Jun. 30, 2018	$ 588,497	(36,356,446)	859,740,325	115,343,948	939,316,324
Balance (in shares) at Jun. 30, 2018	58,849,713
Balance at Mar. 31, 2018	$ 586,402	(35,223,428)	858,109,882	135,940,506	959,413,362
Balance (in shares) at Mar. 31, 2018	58,640,161
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period					(34,992,330)
Balance at Dec. 31, 2018	$ 588,699	(36,356,446)	862,295,309	100,948,176	927,475,738
Balance (in shares) at Dec. 31, 2018	58,869,711
Balance at Jun. 30, 2018	$ 588,497	(36,356,446)	859,740,325	115,343,948	939,316,324
Balance (in shares) at Jun. 30, 2018	58,849,713
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period				(8,177,120)	(8,177,120)
Restricted share award issuances	$ 98		(98)
Restricted share award issuances (in shares)	9,582
Stock-based compensation			1,324,861		1,324,861
Balance at Sep. 30, 2018	$ 588,595	(36,356,446)	861,065,088	107,166,828	932,464,065
Balance (in shares) at Sep. 30, 2018	58,859,295
Increase (Decrease) in Shareholders' Equity
Net income (loss) for the period				(6,218,652)	(6,218,652)
Restricted share award issuances	$ 104		(104)
Restricted share award issuances (in shares)	10,416
Stock-based compensation			1,230,325		1,230,325
Balance at Dec. 31, 2018	$ 588,699	$ (36,356,446)	$ 862,295,309	$ 100,948,176	$ 927,475,738
Balance (in shares) at Dec. 31, 2018	58,869,711