Other Assets - Narrative (Detail) (USD $)	6 Months Ended
	Oct. 27, 2013	Oct. 28, 2012	Apr. 28, 2013
Other Assets Noncurrent [Line Items]
Non-compete agreement carrying amount	$ 1,054,000	$ 259,000	$ 185,000
Other assets [Member]
Other Assets Noncurrent [Line Items]
Gross carrying amount of non-compete agreement	2,000,000	1,100,000	1,100,000
Gross carrying amount of customer relationships	868,000
Number of life insurance contracts owned	2	4	2
Life insurance contracts, death benefits to insured	4,400,000	12,900,000	4,400,000
Other assets [Member] | Non-compete Agreement [Member]
Other Assets Noncurrent [Line Items]
Useful life	15 years
Quarterly payments	12,500
Total remaining non-compete payments	37,500
Final payment date	2014-05
Accumulated amortization	977,000	840,000	940,000
Amortization expense	38,000	99,000
Remaining amortization expense for the remaining fiscal year	37,000
Remaining amortization expense for the second fiscal year	75,000
Remaining amortization expense for the third fiscal year	75,000
Remaining amortization expense for the fourth fiscal year	75,000
Remaining amortization expense for the fifth fiscal year	75,000
Remaining amortization expense for the fiscal year thereafter	755,000
Weighted average remaining amortization period	14 years 6 months
Other assets [Member] | Asset Purchase Agreement Dated August 11, 2008 [Member]
Other Assets Noncurrent [Line Items]
Non-compete agreement carrying amount	201,000
Other assets [Member] | Asset Purchase Agreement Dated May 8, 2013 [Member]
Other Assets Noncurrent [Line Items]
Non-compete agreement carrying amount	853,000
Other assets [Member] | Customer Relationships [Member]
Other Assets Noncurrent [Line Items]
Useful life	17 years
Accumulated amortization	26,000
Amortization expense	26,000
Remaining amortization expense for the remaining fiscal year	26,000
Remaining amortization expense for the second fiscal year	51,000
Remaining amortization expense for the third fiscal year	51,000
Remaining amortization expense for the fourth fiscal year	51,000
Remaining amortization expense for the fifth fiscal year	51,000
Remaining amortization expense for the fiscal year thereafter	$ 612,000
Weighted average remaining amortization period	16 years 6 months