CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	Total	Impact of ASC 326 adoption	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss, net
Beginning balance at Mar. 31, 2018	$ 541,107,852			$ 175,887,227	$ 391,275,705	$ (26,055,080)
Beginning balance (shares) at Mar. 31, 2018			9,119,443
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options (in shares)			92,428
Proceeds from exercise of stock options	5,997,948			5,997,948
Common stock repurchases (in shares)			(665,020)
Common stock repurchases	(74,519,863)				(74,519,863)
Restricted common stock expense under stock option plan, net of cancellations (in shares)			737,267
Restricted common stock expense under stock option plan, net of cancellations	12,248,507			12,248,507
Stock option expense	3,991,967			3,991,967
Other comprehensive loss	(5,235,838)					(5,235,838)
Reclassification of cumulative foreign currency translation adjustments due to sale of Mexico business	31,290,918					31,290,918
Net income	37,235,134				37,235,134
Ending balance (shares) at Mar. 31, 2019			9,284,118
Ending balance at Mar. 31, 2019	552,116,625			198,125,649	353,990,976	0
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options (in shares)			69,481
Proceeds from exercise of stock options	4,612,926			4,612,926
Common stock repurchases (in shares)			(1,520,679)
Common stock repurchases	(197,399,964)				(197,399,964)
Restricted common stock expense under stock option plan, net of cancellations (in shares)			(25,086)
Restricted common stock expense under stock option plan, net of cancellations	18,953,119			18,953,119
Stock option expense	5,522,883			5,522,883
Reclassification of cumulative foreign currency translation adjustments due to sale of Mexico business	0
Net income	$ 28,157,478				28,157,478
Ending balance (shares) at Mar. 31, 2020	7,807,834		7,807,834
Ending balance at Mar. 31, 2020	$ 411,963,067	$ (21,242,249)		227,214,577	184,748,490	0
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options (in shares)			165,237
Proceeds from exercise of stock options	12,268,554			12,268,554
Common stock repurchases (in shares)			(1,129,875)
Common stock repurchases	(102,452,302)				(102,452,302)
Restricted common stock expense under stock option plan, net of cancellations (in shares)			(37,902)
Restricted common stock expense under stock option plan, net of cancellations	12,302,869			12,302,869
Stock option expense	3,804,674			3,804,674
Reclassification of cumulative foreign currency translation adjustments due to sale of Mexico business	0
Net income	$ 88,282,828				88,282,828
Ending balance (shares) at Mar. 31, 2021	6,805,294		6,805,294
Ending balance at Mar. 31, 2021	$ 404,927,441			$ 255,590,674	$ 149,336,767	$ 0