Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Aug. 01, 2018	Apr. 26, 2020	Apr. 28, 2019	Jan. 27, 2019	Jan. 26, 2020
Commitments and Contingencies [Line Items]
Legal recoveries	$ 9.0
Environmental Issue
Commitments and Contingencies [Line Items]
Loss contingency, estimate of probable loss		$ 1.2
Aggregate payments towards remediation plan to date		4.7
Minimum | Environmental Issue
Commitments and Contingencies [Line Items]
Loss contingency, estimate of probable loss		5.9
Maximum | Environmental Issue
Commitments and Contingencies [Line Items]
Loss contingency, estimate of probable loss		7.5
Other Assets
Commitments and Contingencies [Line Items]
Cash surrender value of life insurance		$ 21.5			$ 24.3
Selling, General and Administrative Expenses
Commitments and Contingencies [Line Items]
Legal recoveries			$ 1.0	$ 8.0