Stockholders' Equity (Narrative) (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Cash received from option exercises and purchases of shares under the Purchase Plans	$ 2,400,000	$ 3,100,000	$ 2,300,000
Stock-Based Awards
Total intrinsic value of options exercised	3,300,000	4,600,000	1,400,000
Unamortized stock-based compensation expense related to unvested stock awards	7,400,000
Weighted average period of recognition for unrecognized compensation costs (in years)	2 years 10 months 28 days
Tax benefit attributable to stock options exercised	$ 49,000