Reportable Segments - Summary of Segment Data (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 27, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 27, 2019	Dec. 28, 2018	Dec. 29, 2017
Revenues:
Revenues									$ 1,066.2	$ 1,096.5	$ 924.4
Gross profit:
Total segment gross profit	$ 56.3	$ 47.5	$ 48.2	$ 44.8	$ 45.9	$ 35.0	$ 46.1	$ 48.8	196.8	175.8	167.7
Operating profit:
Total segment operating profit									29.9	60.7	89.5
ASSETS
Total segment assets	1,019.3				965.5				1,019.3	965.5
SPS [Member]
Revenues:
Revenues									840.8	1,015.5	924.4
Gross profit:
Total segment gross profit									121.8	150.3	167.7
Operating profit:
Total segment operating profit									18.3	52.3	$ 89.5
ASSETS
Total segment assets	828.0				803.7				828.0	803.7
SSB [Member]
Revenues:
Revenues									225.4	81.0
Gross profit:
Total segment gross profit									75.0	25.5
Operating profit:
Total segment operating profit									11.6	8.4
ASSETS
Total segment assets	$ 191.3				$ 161.8				$ 191.3	$ 161.8