Fair Value of Financial Instruments - Recurring Basis (Detail) - USD ($) $ in Thousands	Apr. 29, 2018	Apr. 30, 2017
Premier Money Market Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	$ 6,492	$ 4,811
Low Duration Bond Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	1,085	1,081
Intermediate Term Bond Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	747	751
Strategic Income Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	619	611
Large Blend Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	402	365
Growth Allocation Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	169	126
Moderate Allocation Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	113	88
Other [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	150	76
EURO Foreign Exchange Contract [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities measured at fair value on a recurring basis	55
Quoted prices in active markets for identical assets - Level 1 [Member] | Premier Money Market Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	6,492	4,811
Quoted prices in active markets for identical assets - Level 1 [Member] | Low Duration Bond Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	1,085	1,081
Quoted prices in active markets for identical assets - Level 1 [Member] | Intermediate Term Bond Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	747	751
Quoted prices in active markets for identical assets - Level 1 [Member] | Strategic Income Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	619	611
Quoted prices in active markets for identical assets - Level 1 [Member] | Large Blend Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	402	365
Quoted prices in active markets for identical assets - Level 1 [Member] | Growth Allocation Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	169	126
Quoted prices in active markets for identical assets - Level 1 [Member] | Moderate Allocation Fund [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	113	88
Quoted prices in active markets for identical assets - Level 1 [Member] | Other [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured at fair value on a recurring basis	150	$ 76
Significant other observable inputs - Level 2 [Member] | EURO Foreign Exchange Contract [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities measured at fair value on a recurring basis	$ 55