CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) (Parenthetical) (USD $)	9 Months Ended	12 Months Ended
	Dec. 31, 2012	Mar. 31, 2012
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Proceeds from exercise of stock options (in shares)	249,035	324,140
Proceeds from exercise of stock options, tax benefits	$ 2,262,766	$ 2,072,030
Common stock repurchases (in shares)	2,017,677	2,181,045
Issuance of restricted common stock under stock option plan (in shares)	439,500	60,416