Stock-Based Compensation Outstanding Stock Options (Details 2) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2015	Mar. 31, 2014
Stock based compensation disclosure
Allocated Share-based Compensation Expense	$ 18,171	$ 18,193	$ 37,041	$ 34,699
Employee Stock Option
Stock based compensation disclosure
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	19,716		19,716
Allocated Share-based Compensation Expense	$ 2,234	$ 2,953	$ 5,039	$ 6,217
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	4,728	4,742	4,728	4,742	4,432	4,801
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 38.04	$ 39.52	$ 38.04	$ 39.52	$ 39.58	$ 43.02
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			876	916
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 54.52	$ 47.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(192)	(453)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price			$ 32.42	$ 30.76
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period			(388)	(522)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price			$ 95.68	$ 93.59