Restructuring and impairment charges (credits) - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	May 01, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring costs expected cash payment		$ 1.0		$ 1.0
2019 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs expected cash payment	$ 1.0		$ 1.7
Restructuring reserve	11.8		11.8
2019 Footprint realignment plan | Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges					$ 56.0
2019 Footprint realignment plan | Minimum | Accelerated Depreciation And Other Costs
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges					36.0
2019 Footprint realignment plan | Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges					70.0
2019 Footprint realignment plan | Maximum | Accelerated Depreciation And Other Costs
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges					$ 45.0
2018 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs expected cash payment	0.7		1.3
Restructuring reserve	45.0		45.0
Aggregate restructuring charges incurred	53.9		53.9
Restructuring expenses			5.4
2018 Footprint realignment plan | Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	102.0		102.0
2018 Footprint realignment plan | Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	133.0		133.0
2014 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	3.8		3.8
Aggregate restructuring charges incurred	12.8		12.8
Restructuring expenses			30.5
2014 Footprint realignment plan | Accelerated Depreciation And Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0.7	$ 0.6	1.3	$ 1.0
2014 Footprint realignment plan | Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	47.0		47.0
2014 Footprint realignment plan | Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	$ 52.0		$ 52.0