Earnings Per Share and Stock Plans (Summary of Option Transactions) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Exercised	(87,210)	(229,516)	(39,878)
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Outstanding, at Beginning of the year	612,506	736,301
Granted	118,060	136,793	159,212
Exercised	(87,210)	(230,619)	(39,858)
Cancelled	(31,207)	(29,969)	(25,060)
Number of options, Outstanding, Closing Balance	612,149	612,506	736,301
Exercisable at end of period	309,435
Beginning of year, Average Option Price	17.05	14.46
Granted	27.08	18.95	13.43
Exercised	18.41	9.51	7.39
Cancelled	15.71	20.00	19.22
End of year, Average Option Price	18.86	17.05	14.46
End of year, Average Exercisable Price	17.05
Outstanding at period end, Weighted average Remaining Contractual Life (in years)	6 years 5 months 1 day
Exercisable at period end, Weighted average Remaining Contractual Life (in years)	5 years 4 months 13 days
Outstanding at end of period, Aggregate Intrinsic Value	4,990
Exercisable at end of period, Aggregate Intrinsic Value	3,083