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Stock-Based Compensation - Weighted Average Assumptions to Calculate Fair Values of Options Granted (Detail) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012 Minimum [Member]	Oct. 02, 2011 Minimum [Member]	Sep. 30, 2012 Maximum [Member]	Oct. 02, 2011 Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of options (years)	4 years 6 months	4 years 3 months 18 days	4 years 2 months 12 days		4 years 6 months	4 years 3 months 18 days
Risk-free interest rate	0.50%	0.90%	0.50%	0.90%	0.60%	1.50%
Expected volatility	41.00%	42.00%	41.00%	41.00%	42.00%	42.00%
Expected dividend yield
Weighted average estimated fair value	$ 2.68	$ 2.01			$ 2.72	$ 2.12

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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