Pension and retirement plans (Pension Plans) (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jun. 27, 2015
Changes in benefit obligations:
Benefit obligations at beginning of year	$ 588,511	$ 513,406
Acquired benefit obligations	165,046
Service cost	29,623	39,740	$ 39,492
Interest cost	19,323	21,310	17,797
Actuarial loss	15,686	41,799
Benefits paid	(46,121)	(27,744)
Benefit obligations at end of year	772,068	588,511	513,406
Change in plan assets:
Fair value of plan assets at beginning of year	516,089	484,408
Acquired plan assets	144,238
Actual return on plan assets	51,409	19,425
Benefits paid	(46,121)	(27,744)
Contributions	33,750	40,000
Fair value of plan assets at end of year	699,365	516,089	$ 484,408
Funded status of the plan recognized as a non-current liability	(72,703)	(72,422)
Amounts recognized in accumulated other comprehensive income:
Unrecognized net actuarial losses	234,863	235,747
Unamortized prior service credits	(691)	(2,903)
Amount recognized in accumulated other comprehensive income	234,172	232,844
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net actuarial gain	9,744	62,659
Amortization of net actuarial losses	(14,440)	(12,731)
Amortization of prior service credits	1,573	1,573
Curtailment recognition of prior service credit	614
Other changes in plan assets and benefit obligations recognized in other comprehensive income	$ (2,509)	$ 51,501
Weighted average assumptions used to calculate actuarial present values of benefit obligations
Discount rate	3.80%	3.40%
Weighted average assumptions used to determine net benefit costs
Discount rate	3.30%	4.30%
Expected return on plan assets	8.00%	8.30%