Income Taxes - U.S. and Foreign Components of Income before Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Income Tax Disclosure [Abstract]
United States	$ (24.5)	$ (49.7)	$ (5.0)
Foreign	124.2	52.0	57.3
Income before provision for income taxes	$ 99.7	$ 2.3	$ 52.3