Loans Payable and Long-Term Debt (Narrative) (Details) - USD ($)					12 Months Ended
	Apr. 26, 2021	Apr. 22, 2021	Dec. 29, 2017	Jan. 25, 2016	Apr. 30, 2022	Apr. 30, 2021	Mar. 08, 2022	Feb. 12, 2018
Debt Instrument [Line Items]
Debt, outstanding balance					$ 512,552,000	$ 526,153,000
New Markets Tax Credit Investment				$ 2,300,000
New Markets Tax Credit, Recapture Period				7 years
Debt issuance costs					3,556,000	4,381,000
Debt Instrument, Repurchase Date	Apr. 26, 2021
Amortization of intangible assets					45,700,000	47,900,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	102.438%
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
LIBOR rate				1.20%
Loan agreement amount				$ 6,600,000			$ 400,000
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
Liability | Debt
Debt Instrument [Line Items]
Outstanding amounts under finance lease obligations					5,000,000	5,500,000
Initial Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Loan agreement amount			$ 250,000,000
Proceeds from Issuance of Debt			250,000,000
Initial Term Loan And Delayed Draw Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						250,000,000
Delayed Draw Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
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%
Term Loans [Member]
Debt Instrument [Line Items]
Debt, outstanding balance					$ 237,500,000	250,000,000
Term Loans [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Loan agreement amount		$ 250,000,000
Proceeds from Issuance of Debt		250,000,000
Long-term Debt, Gross						237,500,000
Minimum [Member]
Debt Instrument [Line Items]
Interest rates on finance leases (percent)					2.00%
Maximum [Member]
Debt Instrument [Line Items]
Interest rates on finance leases (percent)					4.60%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amount outstanding					$ 263,000,000	264,000,000
Proceeds from term loan		264,000,000	50,000,000
Line of credit facility, maximum borrowing capacity		500,000,000	100,000,000
Line of Credit Facility, Remaining Borrowing Capacity					$ 225,300,000	227,700,000
Line of Credit Facility, Commitment Fee Percentage					0.20%
Consolidated Interest Coverage Ratio					2.00
Total Net Leverage Ratio					4.00
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 50,000,000	$ 25,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Amount outstanding					$ 11,700,000	$ 8,300,000
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Spread on interest rate					2.00%
Base Rate | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Spread on interest rate					1.00%