Other Assets - Narrative (Detail)	3 Months Ended
	Jul. 31, 2016 USD ($) Contract	Aug. 02, 2015 USD ($) Contract	May 01, 2016 USD ($) Contract
Other Assets [Line Items]
Gross carrying amount of non-compete agreement	$ 2,000,000	$ 2,000,000	$ 2,000,000
Gross carrying amount of customer relationships	$ 868,000	$ 868,000	$ 868,000
Number of life insurance contracts owned | Contract	1	1	1
Life insurance contracts, death benefits to insured	$ 1,400,000	$ 1,400,000	$ 1,400,000
Life insurance contracts, cash surrender value	$ 358,000	339,000	357,000
Non-compete Agreement [Member]
Other Assets [Line Items]
Useful life	15 years
Accumulated amortization	$ 1,100,000	1,000,000	1,100,000
Amortization expense	19,000	19,000
Remaining amortization expense for the fiscal year	56,000
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	$ 529,000
Weighted average remaining amortization period	11 years 9 months 18 days
Customer Relationships [Member]
Other Assets [Line Items]
Useful life	17 years
Accumulated amortization	$ 166,000	115,000	$ 153,000
Amortization expense	13,000	$ 13,000
Remaining amortization expense for the fiscal year	38,000
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	$ 460,000
Weighted average remaining amortization period	13 years 9 months 18 days