Restructuring and impairment charges - additional information (Detail) - USD ($)	3 Months Ended		6 Months Ended		13 Months Ended	14 Months Ended	16 Months Ended	30 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 28, 2015	Jun. 28, 2015	Jun. 28, 2015
Restructuring Cost And Reserve [Line Items]
Restructuring charges	$ 580,000	$ 7,623,000	$ 5,028,000	$ 15,403,000
Impairment charges	0	0	0	0
Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	261,000	(1,223,000)	901,000	(1,695,000)
Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	267,000	(122,000)	359,000	254,000
Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges	64,000	202,000	82,000	202,000
2015 Restructuring Program
Restructuring Cost And Reserve [Line Items]
Restructuring charges	142,000		4,380,000
Restructuring reserve	3,500,000		3,500,000		$ 3,500,000	$ 3,500,000	$ 3,500,000	$ 3,500,000
2015 Restructuring Program | Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	24,000		645,000
2015 Restructuring Program | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	63,000		129,000
2015 Restructuring Program | Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges	46,000		47,000
2015 Restructuring Program | Minimum
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	6,000,000		6,000,000		6,000,000	6,000,000	6,000,000	6,000,000
2015 Restructuring Program | Maximum
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	7,000,000		7,000,000		7,000,000	7,000,000	7,000,000	7,000,000
2014 Manufacturing Footprint Realignment
Restructuring Cost And Reserve [Line Items]
Restructuring expenses	3,600,000		5,900,000			10,000,000
Restructuring charges	507,000	8,577,000	670,000	8,577,000
Restructuring reserve	7,500,000		7,500,000		7,500,000	7,500,000	7,500,000	7,500,000
2014 Manufacturing Footprint Realignment | Accelerated Depreciation And Other Costs
Restructuring Cost And Reserve [Line Items]
Restructuring expenses						10,100,000
Restructuring and Related Cost, Accelerated Depreciation	3,100,000		5,200,000
2014 Manufacturing Footprint Realignment | Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	228,000	0	228,000	0
2014 Manufacturing Footprint Realignment | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	204,000	0	230,000	0
2014 Manufacturing Footprint Realignment | Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	0	0	0
2014 Manufacturing Footprint Realignment | Minimum
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	37,000,000		37,000,000		37,000,000	37,000,000	37,000,000	37,000,000
Restructuring costs expected cash payment	26,000,000		26,000,000		26,000,000	26,000,000	26,000,000	26,000,000
2014 Manufacturing Footprint Realignment | Minimum | Termination Benefits
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	11,000,000		11,000,000		11,000,000	11,000,000	11,000,000	11,000,000
2014 Manufacturing Footprint Realignment | Minimum | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	2,000,000		2,000,000		2,000,000	2,000,000	2,000,000	2,000,000
2014 Manufacturing Footprint Realignment | Minimum | Accelerated Depreciation Charges
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	10,000,000		10,000,000		10,000,000	10,000,000	10,000,000	10,000,000
2014 Manufacturing Footprint Realignment | Minimum | Other
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	14,000,000		14,000,000		14,000,000	14,000,000	14,000,000	14,000,000
2014 Manufacturing Footprint Realignment | Maximum
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	44,000,000		44,000,000		44,000,000	44,000,000	44,000,000	44,000,000
Restructuring costs expected cash payment	31,000,000		31,000,000		31,000,000	31,000,000	31,000,000	31,000,000
2014 Manufacturing Footprint Realignment | Maximum | Termination Benefits
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	13,000,000		13,000,000		13,000,000	13,000,000	13,000,000	13,000,000
2014 Manufacturing Footprint Realignment | Maximum | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	3,000,000		3,000,000		3,000,000	3,000,000	3,000,000	3,000,000
2014 Manufacturing Footprint Realignment | Maximum | Accelerated Depreciation Charges
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	11,000,000		11,000,000		11,000,000	11,000,000	11,000,000	11,000,000
2014 Manufacturing Footprint Realignment | Maximum | Other
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	17,000,000		17,000,000		17,000,000	17,000,000	17,000,000	17,000,000
2014 European Restructuring Plan
Restructuring Cost And Reserve [Line Items]
Restructuring expenses							7,900,000
Restructuring charges	18,000	(212,000)	43,000	8,106,000
Restructuring reserve	400,000		400,000		400,000	400,000	400,000	400,000
2014 European Restructuring Plan | Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	305,000	0	305,000
2014 European Restructuring Plan | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	0	0	0
2014 European Restructuring Plan | Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges	18,000	49,000	34,000	49,000
2014 Restructuring Program
Restructuring Cost And Reserve [Line Items]
Restructuring charges		1,781,000	49,000	1,781,000	3,600,000
Restructuring reserve	600,000		600,000		600,000	600,000	600,000	600,000
2014 Restructuring Program | Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges		1,174,000	49,000	1,174,000
2014 Restructuring Program | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges		0	0	0
2014 Restructuring Program | Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges		131,000	0	131,000
2014 Restructuring Program | Maximum
Restructuring Cost And Reserve [Line Items]
Expected restructuring charges	4,000,000		4,000,000		4,000,000	4,000,000	4,000,000	4,000,000
LMA Restructuring Program
Restructuring Cost And Reserve [Line Items]
Restructuring charges	9,000	(2,942,000)	(20,000)	(3,372,000)				11,300,000
LMA Restructuring Program | Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	9,000	(2,759,000)	(21,000)	(3,231,000)
LMA Restructuring Program | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	(154,000)	0	(112,000)
LMA Restructuring Program | Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	0	1,000	0
2013 Restructuring Program
Restructuring Cost And Reserve [Line Items]
Restructuring charges	(96,000)	396,000	(94,000)	564,000				11,000,000
2013 Restructuring Program | Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	57,000	0	57,000
2013 Restructuring Program | Facility Closure Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	0	0	0
2013 Restructuring Program | Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges	0	$ 22,000	0	$ 22,000
2012 Restructuring Charges
Restructuring Cost And Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date	6,300,000		6,300,000		6,300,000	6,300,000	6,300,000	6,300,000
Restructuring reserve	$ 500,000		$ 500,000		$ 500,000	$ 500,000	$ 500,000	$ 500,000