Stock-Based Compensation (ESPP - Purchase Option Activity) (Details) (Employee Stock Purchase Plan [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding at the beginning of period, Number Of Stock Options	62,137	79,208	66,828
Granted, Number Of Stock Options	211,093	244,122	295,327
Exercised, Number Of Stock Options	(218,109)	(261,193)	(282,947)
Outstanding at the end of period, Number Of Stock Options	55,121	62,137	79,208
Outstanding at the beginning of period, Weighted-Average Exercise Price Per Share	$ 68.74	$ 51.61	$ 51.03
Granted, Weighted-Average Exercise Price Per Share	$ 82.88	$ 70.74	$ 53.95
Exercised, Weighted-Average Exercise Price Per Share	$ 79.38	$ 65.42	$ 53.92
Outstanding at the end of period, Weighted-Average Exercise Price Per Share	$ 80.77	$ 68.74	$ 51.61
Outstanding at the end of period, Aggregate Intrinsic Value	$ 1,419	$ 1,890	$ 2,959