XML 59 R64.htm IDEA: XBRL DOCUMENT

Share-Based Payments - Summary of weighted-average assumptions (Details) (Stock options)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.71%	1.84%	1.88%
Weighted average expected original term	5 years	5 years	5 years
Expected volatility	48.00%	49.00%	49.00%
Expected dividend yield	3.20%	0.00%	0.00%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References+ Details