Stock-Based Compensation (ESPP - Purchase Option Activity) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Exercised	(381)
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding at March 31, 2014	55
Granted	195
Exercised	(103)
Outstanding at September 30, 2014	147
Outstanding at March 31, 2014, Weighted-Average Exercise Price Per Share	$ 80.77
Granted, Weighted-Average Exercise Price Per Share	$ 91.38
Exercised, Weighted-Average Exercise Price Per Share	$ 87.17
Outstanding at September 30, 2014, Weighted-Average Exercise Price Per Share	$ 90.35