Stock-Based Compensation (Details 2) (Black-Scholes option pricing model)	6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Black-Scholes option pricing model
Share-based Compensation Arrangement by Share Based Payment Award Fair Value Assumptions
Expected dividend yield (as a percent)	1.39%	1.39%
Risk-free interest rate (as a percent)	1.95%	2.40%
Expected volatility (as a percent)	47.16%	52.83%
Expected lives (in years)	5.12	5.18