Condensed Consolidated Statements of Shareholders' Equity - USD ($)	Common stock	Treasury stock	Additional paid-in capital	Retained earnings	Total
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)				(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)					(28,773,678)
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
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)				(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
Balance at Mar. 31, 2019	$ 588,826	(36,484,561)	863,583,692	84,994,601	912,682,558
Balance (in shares) at Mar. 31, 2019	58,882,515
Increase (Decrease) in Shareholders' Equity
Net income/(loss)				6,075,059	6,075,059
Restricted share award issuances	$ 78		(78)
Restricted share award issuances (in shares)	7,750
Stock-based compensation			1,305,827		1,305,827
Purchase of treasury stock		(983,582)			(983,582)
Balance at Jun. 30, 2019	$ 588,904	(37,468,143)	864,889,441	91,069,660	919,079,862
Balance (in shares) at Jun. 30, 2019	58,890,265
Balance at Mar. 31, 2019	$ 588,826	(36,484,561)	863,583,692	84,994,601	912,682,558
Balance (in shares) at Mar. 31, 2019	58,882,515
Increase (Decrease) in Shareholders' Equity
Net income/(loss)					46,786,955
Balance at Sep. 30, 2019	$ 590,736	(43,778,657)	865,778,309	131,781,556	954,371,944
Balance (in shares) at Sep. 30, 2019	59,073,485
Balance at Jun. 30, 2019	$ 588,904	(37,468,143)	864,889,441	91,069,660	919,079,862
Balance (in shares) at Jun. 30, 2019	58,890,265
Increase (Decrease) in Shareholders' Equity
Net income/(loss)				40,711,896	40,711,896
Restricted share award issuances	$ 1,832		(1,832)
Restricted share award issuances (in shares)	183,220
Stock-based compensation			890,700		890,700
Purchase of treasury stock		(6,310,514)			(6,310,514)
Balance at Sep. 30, 2019	$ 590,736	$ (43,778,657)	$ 865,778,309	$ 131,781,556	$ 954,371,944
Balance (in shares) at Sep. 30, 2019	59,073,485