Effective Income Tax Rate Reconciliation, Current Tax on Foreign Income, Amount

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Investment Tax Credit, Foreign, Percentage of Qualified Expenditures

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Operating Loss Carryforwards, Potential Tax Benefit

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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to foreign tax credit.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount of unrecognized tax benefits.

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Amount of interest expense accrued for an underpayment of income taxes.

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Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended								4 Months Ended	8 Months Ended	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Millions	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 28, 2018	Dec. 31, 2017	Apr. 27, 2019	Apr. 28, 2018	Apr. 29, 2017
Tax Credit Carryforward [Line Items]
Deferred Income Tax Liabilities, Net	$ 2.1										$ 2.1
Income tax at statutory rate (as a percent)									21.00%	35.00%	21.00%	30.50%	35.00%
Foreign Investment Tax Credit	0.2	$ (0.7)	$ (1.1)	$ (0.4)	$ (8.7)	$ (0.3)	$ (0.4)	$ (0.4)			$ (2.0)	$ (9.8)	$ (4.7)
Current Taxation of Foreign Income											3.4	0.0	0.0
Income tax expense (benefit)											12.0	66.6	23.0
Deferred income tax assets, net					24.0				$ 24.0			24.0
Valuation allowance	6.3				2.5				2.5		6.3	2.5
Income taxes paid											27.8	20.2	19.0
Gross unrecognized tax benefits	3.1				1.4				$ 1.4		3.1	1.4	$ 1.3
Interest on income taxes accrued	0.1										0.1
Internal Revenue Service (IRS)
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	9.0										9.0
Federal income tax benefit	5.3										5.3
State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	4.8										4.8
Federal income tax benefit	$ 0.9										$ 0.9
Foreign tax authority \| Investment Tax Credit Carryforward \| Malta
Tax Credit Carryforward [Line Items]
Percentage of qualified expenditures subject to investment tax credit	30.00%										30.00%
Total unused credits	$ 28.2										$ 28.2
Tax Credit Carryforward, Period, 2020 Expiration \| Foreign tax authority \| Investment Tax Credit Carryforward \| Malta
Tax Credit Carryforward [Line Items]
Total unused credits	0.8										0.8
Tax Credit Carryforward, Period, Indefinite \| Foreign tax authority \| Investment Tax Credit Carryforward \| Malta
Tax Credit Carryforward [Line Items]
Total unused credits	27.4										27.4
Total Impact of U.S. Tax Reform
Tax Credit Carryforward [Line Items]
Income tax expense (benefit)	$ 0.0	$ (4.8)	$ 0.0	$ 0.0	$ (3.1)	$ 56.8	$ 0.0	$ 0.0			$ (4.8)	$ 53.7