CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) - USD ($)	Total	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]	Employee Stock Option [Member]
Common Stock, Shares, Outstanding	8,782,949
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	155,710
Balances at Mar. 31, 2017	$ 461,063,577	$ 144,241,105	$ 344,605,347	$ (27,782,875)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options, including tax benefits	$ 8,736,340
Stock Repurchased and Retired During Period, Shares	(58,728)
Stock Repurchased and Retired During Period, Value			(4,614,331)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	(11,535)
Issuance of restricted common stock under stock option plan	$ 655,620	655,620
Stock option expense	1,834,513	1,834,513
Other comprehensive income	(3,282,203)			(3,282,203)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0
Net income	24,547,248		24,547,248
Balances at Dec. 31, 2017	$ 488,940,764	157,872,907	362,132,935	(31,065,078)
Common Stock, Shares, Outstanding	8,840,040
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	39,891
Balances at Sep. 30, 2017	$ 490,152,309	155,823,825	360,452,718	(26,124,234)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options, including tax benefits	$ 1,971,294	1,971,294
Stock Repurchased and Retired During Period, Shares	0
Stock Repurchased and Retired During Period, Value			0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	(11,535)
Issuance of restricted common stock under stock option plan	$ (634,498)	(634,498)
Stock option expense	712,286	712,286
Other comprehensive income	(4,940,844)			(4,940,844)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0
Net income	1,680,217		1,680,217
Balances at Dec. 31, 2017	$ 488,940,764	157,872,907	362,132,935	(31,065,078)
Common Stock, Shares, Outstanding	8,868,396
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (2,405,329)
Common Stock, Shares, Outstanding	9,119,443
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	45,456				45,456
Balances at Mar. 31, 2018	$ 541,107,852	175,887,227	391,275,705	(26,055,080)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options, including tax benefits	$ 2,815,599	2,815,599
Stock Repurchased and Retired During Period, Shares	(38,822)
Stock Repurchased and Retired During Period, Value			3,760,309
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	713,271
Issuance of restricted common stock under stock option plan	$ 6,131,165	6,131,165
Stock option expense	2,424,986	2,424,986
Other comprehensive income	(5,235,838)			(5,235,838)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	31,290,918
Net income	(705,487)		(705,487)
Balances at Dec. 31, 2018	$ 574,068,886	187,258,977	386,809,909	0
Common Stock, Shares, Outstanding	9,153,145
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	20,180
Balances at Sep. 30, 2018	$ 564,990,675	180,680,619	384,310,056	0
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options, including tax benefits	$ 1,000,193	1,000,193
Stock Repurchased and Retired During Period, Shares	(38,822)
Stock Repurchased and Retired During Period, Value			(3,760,309)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	704,845
Issuance of restricted common stock under stock option plan	$ 4,216,816	4,216,816
Stock option expense	1,361,349	1,361,349
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0
Net income	6,260,162		6,260,162
Balances at Dec. 31, 2018	$ 574,068,886	$ 187,258,977	$ 386,809,909	$ 0
Common Stock, Shares, Outstanding	9,839,348