Loans Payable and Long-Term Debt (Narrative) (Details) - USD ($)			12 Months Ended
	Dec. 29, 2017	Jan. 25, 2016	Apr. 30, 2020	Apr. 30, 2019	Feb. 12, 2018
Debt Instrument [Line Items]
Debt, outstanding balance			$ 606,346,000	$ 703,305,000
New Markets Tax Credit Investment		$ 2,300,000
New Markets Tax Credit, Recapture Period		7 years
Debt issuance costs			9,209,000	11,814,000
Outstanding amounts under finance lease obligations			5,687,000	6,600,000
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
LIBOR rate		1.20%
Loan agreement amount		$ 6,600,000
Loan term		30 years
Debt issuance costs		$ 300,000
Deferred Finance Costs, Amortization Period		30 years
Other Noncurrent Assets [Member]
Debt Instrument [Line Items]
Financing Receivable, after Allowance for Credit Loss, Noncurrent		$ 4,300,000
Long-term Debt [Member]
Debt Instrument [Line Items]
Amount drawn on loan			6,700,000
Initial Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding			122,000,000	170,000,000
Loan agreement amount	$ 250,000,000
Initial Term Loan And Delayed Draw Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding			244,000,000	340,000,000
Delayed Draw Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding			170,000,000	230,000,000
Loan agreement amount	250,000,000
4.875% Senior Notes Due 2026 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Loan agreement amount					$ 350,000,000
Debt instrument, interest rate, stated percentage					4.875%
RSI Notes [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			330,000,000
Long-term Debt			$ 350,000,000
Minimum [Member]
Debt Instrument [Line Items]
Interest rates on finance leases (percent)			3.50%
Maximum [Member]
Debt Instrument [Line Items]
Interest rates on finance leases (percent)			6.50%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amount outstanding			$ 0	$ 0
Total Secured Debt To EBITDA Ratio			2.50
Proceeds from term loan	50,000,000
Line of Credit Facility, Commitment Fee Percentage			0.175%
Total Funded Debt to EBITDA Ratio, thereafter			3.25
Total Funded Debt to EBITDA Ratio upon Qualified Acquisition			3.75
Fixed Charge Coverage Ratio			1.25
Total Funded Debt to EBITDA Ratio to Permit Unlimited Restricted Payments			2.50
Debt Covenant, Permitted Restricted Payments			$ 50,000,000
Total Funded Debt to EBITDA Ratio, applicable to the exception permitting unlimited restricted payments, amended			2.75
Revolving Credit Facility [Member] | Wells Fargo [Member]
Debt Instrument [Line Items]
Line Of Credit Facility, Agreement Terminated	35,000,000
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on interest rate			0.50%
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on interest rate			1.50%
RSI Home Products, Inc. [Member]
Debt Instrument [Line Items]
Indebtedness assumed (including accrued interest)	$ 589,000,000
RSI Home Products, Inc. [Member] | Initial Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Loan term	5 years
RSI Home Products, Inc. [Member] | RSI Notes [Member]
Debt Instrument [Line Items]
Indebtedness assumed (including accrued interest)	$ 589,000,000
RSI Home Products, Inc. [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Proceeds from term loan	$ 50,000,000