Stock Based Compensation and Stock Options - Stock Options (Detail) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning, Shares	1,191,251	1,264,530	1,100,930	1,502,046
Options granted, Shares	142,650	33,300	382,650	96,700
Options exercised, Shares	(69,276)	(57,876)	(188,327)	(261,234)
Options cancelled, Shares	(4,057)	(48,366)	(34,685)	(145,924)
Options outstanding, ending, Shares	1,260,568	1,191,588	1,260,568	1,191,588
Options outstanding, beginning, Average Price	$ 20.39	$ 17.71	$ 18.65	$ 17.10
Options granted, Average Price	$ 40.24	$ 21.61	$ 31.14	$ 21.56
Options exercised, Average Price	$ 16.33	$ 12.45	$ 15.14	$ 12.54
Options cancelled, Average Price	$ 21.90	$ 22.29	$ 22.94	$ 21.79
Options outstanding, ending, Average Price	$ 22.85	$ 17.88	$ 22.85	$ 17.88