Derivative financial instruments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 30, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative financial instrument (loss) gain	$ (1,361)	$ 771	$ 1,715	$ (8,737)
Other expenses, net
Derivative Instruments, Gain (Loss) [Line Items]
Derivative financial loss		$ 27,000		$ 35,000