Income Taxes - Income Tax Expense (Parenthetical) (Detail) $ in Thousands	12 Months Ended
	Apr. 29, 2018 USD ($)
Income Tax Disclosure [Abstract]
2017 Tax Cuts and Jobs Act income tax benefit	$ 6,903	[1]
establishment of valuation allowance	$ 4,550	[2]

[1] The income tax benefit of $6,903 includes a charge of $4,550 for the establishment of a valuation allowance against U.S. foreign tax credits that are more-likely-than not to be realized as a result of the 2017 Tax Cuts and Jobs Act.

[2] The establishment of this valuation allowance pertains to U.S. foreign tax credits that are more-likely-than not to be realized as a result of the Tax Act.