Restructuring, acquisition and integration-related costs (Restructuring and Related Costs by Type of Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014
Restructuring Cost and Reserve [Line Items]
Acquisition transaction-related costs	$ 3,701		$ 4,678
Restructuring, acquisition and integration-related costs			13,818	$ 8,751
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	10,463	$ 3,475	20,307	5,534
Acquisition integration-related costs	1,878	3,280	2,010	6,858
Restructuring, acquisition and integration-related costs	12,341	6,755	22,317	12,392
Accelerated depreciation included in restructuring costs	3,210		7,570
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	(92)	615	1,081	3,217
Acquisition integration-related costs	2,535	3,799	2,938	7,285
Acquisition transaction-related costs	3,701	0	4,678	0
Restructuring, acquisition and integration-related costs	$ 6,144	$ 4,414	$ 8,697	$ 10,502