Derivative financial instruments (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 17, 2016	Dec. 31, 2016	Jan. 02, 2016	Dec. 31, 2016	Jan. 02, 2016	Jul. 02, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Reduction in acquisition price due to foreign currency hedge	$ 75,000
Average length of time of Foreign exchange contracts				49 days		53 days
Not Designated as Hedging Instrument | Foreign Exchange Forward
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		$ 771	$ (5,461)	$ (8,737)	$ (1,789)
Other expenses, net
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative financial instrument gain (loss)		$ (27,000)		$ (35,000)