Goodwill and other intangible assets, net - Components of intangible assets (Details) - USD ($) $ in Thousands	Sep. 25, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (461,480)	$ (412,671)
Gross carrying amount	1,626,124	1,612,646
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	630,127	621,078
Accumulated amortization	(235,074)	(214,924)
Intellectual property
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	523,361	522,374
Accumulated amortization	(197,465)	(173,903)
Distribution rights
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	23,356	23,279
Accumulated amortization	(15,294)	(14,393)
Trade names
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	387,759	384,821
Accumulated amortization	(12,734)	(8,929)
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	2,853	2,186
Accumulated amortization	(913)	(522)
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	58,668	58,908
Accumulated amortization	$ 0	$ 0