Condensed Consolidated Statements of Shareholders Equity - USD ($)	Common stock	Treasury stock	Additional paid-in capital	Retained earnings	Total
Balance at Mar. 31, 2020	$ 590,833	$ (87,183,865)	$ 866,809,371	$ 196,835,859	$ 977,052,198
Balance (in shares) at Mar. 31, 2020	59,083,290
Increase (Decrease) in Shareholders' Equity
Net income for the period				12,168,005	12,168,005
Restricted share award issuances	$ 3,516		(3,516)
Restricted share award issuances (in shares)	351,629
Stock-based compensation			1,930,902		1,930,902
Purchase of treasury stock		(1,198,214)			(1,198,214)
Balance at Jun. 30, 2020	$ 594,349	(88,382,079)	868,736,757	209,003,864	989,952,891
Balance (in shares) at Jun. 30, 2020	59,434,919
Balance at Mar. 31, 2020	$ 590,833	(87,183,865)	866,809,371	196,835,859	977,052,198
Balance (in shares) at Mar. 31, 2020	59,083,290
Increase (Decrease) in Shareholders' Equity
Net income for the period					12,705,955
Balance at Sep. 30, 2020	$ 594,500	(89,688,467)	869,143,327	209,541,814	989,591,174
Balance (in shares) at Sep. 30, 2020	59,450,019
Balance at Jun. 30, 2020	$ 594,349	(88,382,079)	868,736,757	209,003,864	989,952,891
Balance (in shares) at Jun. 30, 2020	59,434,919
Increase (Decrease) in Shareholders' Equity
Net income for the period				537,950	537,950
Restricted share award issuances	$ 151		(151)
Restricted share award issuances (in shares)	15,100
Stock-based compensation			406,721		406,721
Purchase of treasury stock		(1,306,388)			(1,306,388)
Balance at Sep. 30, 2020	$ 594,500	(89,688,467)	869,143,327	209,541,814	989,591,174
Balance (in shares) at Sep. 30, 2020	59,450,019
Balance at Mar. 31, 2021	$ 510,715	(99,862,114)	756,776,217	289,400,512	946,825,330
Balance (in shares) at Mar. 31, 2021	51,071,409
Increase (Decrease) in Shareholders' Equity
Net income for the period				5,869,100	5,869,100
Restricted share award issuances	$ 158		(158)
Restricted share award issuances (in shares)	15,800
Stock-based compensation			647,124		647,124
Purchase of treasury stock		(14,793,180)			(14,793,180)
Balance at Jun. 30, 2021	$ 510,873	(114,655,294)	757,423,183	295,269,612	938,548,374
Balance (in shares) at Jun. 30, 2021	51,087,209
Balance at Mar. 31, 2021	$ 510,715	(99,862,114)	756,776,217	289,400,512	946,825,330
Balance (in shares) at Mar. 31, 2021	51,071,409
Increase (Decrease) in Shareholders' Equity
Net income for the period					19,970,903
Balance at Sep. 30, 2021	$ 512,757	(121,209,001)	758,711,553	268,933,981	906,949,290
Balance (in shares) at Sep. 30, 2021	51,275,609
Balance at Jun. 30, 2021	$ 510,873	(114,655,294)	757,423,183	295,269,612	938,548,374
Balance (in shares) at Jun. 30, 2021	51,087,209
Increase (Decrease) in Shareholders' Equity
Net income for the period				14,101,803	14,101,803
Restricted share award issuances	$ 1,884		(1,884)
Restricted share award issuances (in shares)	188,400
Dividend				(40,437,434)	(40,437,434)
Stock-based compensation			1,290,254		1,290,254
Purchase of treasury stock		(6,553,707)			(6,553,707)
Balance at Sep. 30, 2021	$ 512,757	$ (121,209,001)	$ 758,711,553	$ 268,933,981	$ 906,949,290
Balance (in shares) at Sep. 30, 2021	51,275,609