Restructuring charges - 2016 Manufacturing Footprint Realignment Plan (Details) - 2016 Manufacturing Footprint Realignment Plan $ in Millions	3 Months Ended
	Mar. 27, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 10.9
Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	10.3
Accelerated Depreciation And Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring cost related to accelerated depreciation	0.6
Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	34.0
Restructuring costs expected cash payment	27.0
Minimum | Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	14.0
Minimum | Facility closure and other exit costs
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	2.0
Minimum | Accelerated Depreciation Charges
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	10.0
Minimum | Other
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	8.0
Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	44.0
Restructuring costs expected cash payment	31.0
Maximum | Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	18.0
Maximum | Facility closure and other exit costs
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	3.0
Maximum | Accelerated Depreciation Charges
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	13.0
Maximum | Other
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	$ 10.0