Stock-Based Compensation (Stock Option Grant Assumptions) (Details) (Stock Option [Member])	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Stock Option [Member]
Valuation Assumption [Line Items]
Expected volatility	40.10%	41.10%	41.90%
Expected dividend yield	1.83%	1.73%	1.42%
Expected term, average years	5 years 8 months	5 years 8 months	5 years 7 months
Risk-free interest rate	0.90%	1.90%	2.10%