Long-Term Debt and Lines of Credit - Long-Term Debt Narrative (Detail) (USD $)	6 Months Ended
	Oct. 27, 2013	Apr. 28, 2013	Oct. 28, 2012	Aug. 11, 2008
Debt Instrument [Line Items]
Principal payment requirements of long-term debt for the first year	$ 2,200,000
Principal payment requirements of long-term debt for the second year	2,200,000
Long-term Debt	4,400,000	6,600,000	6,817,000
Long-term debt, fair value	4,600,000	7,000,000	7,000,000
Unsecured senior term notes [Member]
Debt Instrument [Line Items]
Issuance of unsecured term notes				11,000,000
Fixed interest rate				8.01%
Term of the note agreement	7 years
Required amount of principal payment installments	2,200,000
Date of first required principal payment	Aug. 11, 2011
Required debt payment frequency	Annual
Average term period for remaining principal payments, in years	1 year 9 months 18 days
Maturity date	Aug. 11, 2015
Long-term Debt	$ 4,400,000	$ 6,600,000	$ 6,600,000