CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) - USD ($)	Total	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]
Balances at Mar. 31, 2015	$ 315,567,719	$ 141,864,764	$ 188,605,305	$ (14,902,350)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options, including tax benefits	3,327,067	3,327,067
Issuance of restricted common stock under stock option plan	(10,322,230)	(10,322,230)
Stock option expense	3,965,463	3,965,463
Other comprehensive income	(8,031,995)			(8,031,995)
Net income	87,395,557		87,395,557
Balances at Mar. 31, 2016	391,901,581	138,835,064	276,000,862	(22,934,345)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options, including tax benefits	(60,560)	(60,560)
Issuance of restricted common stock under stock option plan	423,868	423,868
Stock option expense	982,420	982,420
Other comprehensive income	(7,540,547)			(7,540,547)
Net income	32,109,419		32,109,419
Balances at Sep. 30, 2016	$ 417,816,181	$ 140,180,792	$ 308,110,281	$ (30,474,892)