STOCK-BASED COMPENSATION Valuation Assumptions (Details) (USD $)	12 Months Ended
Mar. 31, 2012 years	Mar. 31, 2011 years	Mar. 31, 2010 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	45.30%	45.70%	53.70%
Risk-free interest rate	1.00%	1.40%	2.00%
Expected dividends	0.60%	0.60%	1.00%
Expected life (in years)	4	4.2	4.5
Weighted-average grant date fair value	$ 12.06	$ 11.92	$ 8.71
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	37.30%	38.70%	49.00%
Risk-free interest rate	0.10%	0.20%	0.20%
Expected dividends	0.60%	0.60%	0.80%
Expected life (in years)	0.5	0.5	0.5
Weighted-average grant date fair value	$ 8.69	$ 8.67	$ 7.22

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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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.

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