Employee Benefits and Deferred Compensation - Additional Information (Detail)	12 Months Ended
	Apr. 24, 2020 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Employee 401(k) Plan, Description	An employee receives the full 4% match when he/she contributes at least 6% of his/her eligible earnings, up to a maximum calendar year matching contribution of $6,000.
Employee contribution percentage	6.00%
Maximum amount of matching contribution	$ 6,000
Defined benefit plan, description of plan amendment	In November 2016, we made certain amendments to the ERM Plan, which prior to amendment, provided group health insurance benefits to eligible retirees. Effective January 1, 2017, the amended ERM Plan provided each eligible retiree with a capped reimbursement of premiums for the period from January 1, 2017 through December 31, 2019. During the period from December 31, 2019 through December 31, 2021, participants in the ERM Plan are eligible to receive a lump sum cash payment equal to two years of projected health care costs, or a prorated portion thereof, pursuant to the methodology set forth in the ERM Plan.
Contribution Match First 2% Eligible Earnings Employee
Defined Contribution Plan Disclosure [Line Items]
Percentage of employee contributions matched	100.00%
Percentage of earnings on employee contributions matched	2.00%
Contribution Match Next 4% Eligible Earnings Employee
Defined Contribution Plan Disclosure [Line Items]
Percentage of employee contributions matched	50.00%
Percentage of earnings on employee contributions matched	4.00%