XML 105 R73.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Fair Value of Financial Instruments - Narrative (Detail) - USD ($)
6 Months Ended
Nov. 03, 2019
Apr. 28, 2019
Oct. 28, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term investments (Rabbi Trust) $ 7,575,000 $ 7,081,000 [1] $ 7,851,000
U.S. Corporate Bonds [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Held to maturity investments   5,000,000 26,700,000
Held to maturity investments, fair value   5,000,000 26,600,000
U.S. Corporate Bonds [Member] | Minimum [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term investments, maturity period 2 years    
U.S. Corporate Bonds [Member] | Maximum [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term investments, maturity period 2 years 6 months    
Long-term investments (Rabbi Trust) [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Accumulated unrealized gain (loss) on investments $ 55,000 $ 40,000 $ 62,000
[1] Derived from audited financial statements.