Segment information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 609,866	$ 528,613	$ 1,197,096	$ 1,016,494
Operating profit	33,490	110,202	120,333	171,021
Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	108,148	126,519	221,192	217,100
Unallocated expenses
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	(74,658)	(16,317)	(100,859)	(46,079)
Vascular North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	80,062	78,796	163,110	157,807
Vascular North America | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	24,636	18,472	49,298	36,762
Interventional North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	64,956	58,337	125,152	98,283
Interventional North America | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	16,510	8,815	30,630	780
Anesthesia North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	50,490	49,081	101,055	97,288
Anesthesia North America | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	14,716	20,056	32,049	33,360
Surgical North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	40,708	44,716	81,385	90,660
Surgical North America | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	17,055	17,287	31,803	33,667
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	153,415	138,469	313,285	272,043
EMEA | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	26,535	23,594	58,305	44,904
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	72,413	65,998	130,657	116,166
Asia | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	20,746	18,941	34,114	29,825
OEM
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	52,594	45,132	98,448	88,478
OEM | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	13,552	10,337	22,568	19,458
All other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	95,228	48,084	184,004	95,769
All other | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating profit	$ (25,602)	$ 9,017	$ (37,575)	$ 18,344