Stock Based Compensation and Stock Options (Details 4) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Options outstanding
Options outstanding, beginning, Shares	632,265	799,034	751,023	813,970
Options outstanding, beginning, Weighted Average Exercise Per Share	$ 35.41	$ 30.62	$ 34.19	$ 29.26
Granted, Number of Options	16,650	95,050	48,350	140,275
Granted, Weighted Average Exercise Per Share	$ 43.22
Options exercised, Shares	(28,938)	(54,366)	(130,617)	(109,339)
Exercised, Weighted Average Exercise Per Share	$ 24.90	$ 27.57	$ 25.08	$ 25.36
Cancelled - forfeited, Number of Options	(23,583)
Cancelled - forfeited, Weighted Average Exercise Per Share	$ 44.93
Cancelled- expired, Number of Options	(600)
Cancelled - expired, Weighted Average Exercise Per Share	$ 31.20
Options outstanding, ending, Shares	595,794	839,559	595,794	839,559
Options outstanding, ending, Weighted Average Exercise Per Share	$ 35.76	$ 33.32	$ 35.76	$ 33.32
Ending outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 2 months 27 days
Ending outstanding, Aggregate Intrinsic Value	$ 6,146,835		$ 6,146,835
Ending vested and expected to vest, Number of Options	536,324		536,324
Ending vested and expected to vest, Weighted Average Exercise Per Share	$ 34.52		$ 34.52
Ending vested and expected to vest, Weighted Average Remaining Contractual Life (Years)	3 years 1 month 21 days
Ending vested and expected to vest, Aggregate Intrinsic Value	6,050,455		6,050,455
Ending exercisable, Number of Options	302,608		302,608
Ending exercisable, Weighted Average Exercise Per Share	$ 28.93		$ 28.93
Ending exercisable, Weighted Average Remaining Contractual Life (Years)	2 years 7 months 17 days
Ending exercisable, Aggregate Intrinsic Value	$ 4,888,979		$ 4,888,979