Stock-Based Compensation (Schedule Of Market-Based Restricted Stock Unit Activity) (Details) (Market-Based Restricted Stock Units [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Sep. 30, 2012
Market-Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Beginning balance	520
Granted	670
Vested	(111)
Forfeited or cancelled	(62)
Ending balance	1,017
Weighted-average grant date fair value, beginning balance	$ 34.77
Weighted-average grant date fair values of restricted stock rights granted	$ 10.45
Weighted-average grant date fair value, vested during period	$ 34.77
Weighted-average grant date fair value, forfeited or cancelled during period	$ 34.77
Weighted-average grant date fair value, ending balance	$ 18.75