Reportable Segments - Summary of Segment Data (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 27, 2020	Mar. 29, 2019	Dec. 27, 2019
Revenues:
Total segment revenues	$ 320.9	$ 260.1
Gross profit:
Total segment gross profit	65.7	44.8
Operating profit:
Total segment operating profit	22.6	8.2
ASSETS
Total segment assets	1,072.2	1,019.3	$ 1,019.3
SPS [Member]
Revenues:
Total segment revenues	259.4	200.2
Gross profit:
Total segment gross profit	44.7	25.7
Operating profit:
Total segment operating profit	20.3	4.3
ASSETS
Total segment assets	872.2	828.0
SSB [Member]
Revenues:
Total segment revenues	61.5	59.9
Gross profit:
Total segment gross profit	21.0	19.1
Operating profit:
Total segment operating profit	2.3	3.9
ASSETS
Total segment assets	$ 200.0	$ 191.3