Net Income Per Share (Calculations Of Basic And Diluted Net Income Per Share And Potential Common Shares) (Details) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net Income Per Share [Abstract]
Net income	$ 7,051	$ 8,248	$ 9,450	$ 15,393
Net income per share-basic	42,258	41,922	42,433	41,867
Basic net income per share	$ 0.17	$ 0.20	$ 0.22	$ 0.37
Weighted average stock options	128	315	163	324
Weighted average restricted stock units	334	541	465	435
Weighted Average Number of Shares Outstanding, Diluted, Total	42,720	42,778	43,061	42,626
Diluted net income per share	$ 0.17	$ 0.19	$ 0.22	$ 0.36