Pension and retirement plans (Pension Plans) (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Jul. 02, 2016	Jun. 27, 2015	Jun. 28, 2014
Changes in benefit obligations:
Benefit obligations at beginning of year	$ 513,406	$ 457,167
Service cost	39,740	39,492	$ 36,733
Interest cost	21,310	17,797	17,155
Actuarial loss	41,799	21,796
Benefits paid	(27,744)	(22,846)
Benefit obligations at end of year	588,511	513,406	457,167
Change in plan assets:
Fair value of plan assets at beginning of year	484,408	449,960
Actual return on plan assets	19,425	17,294
Benefits paid	(27,744)	(22,846)
Contributions	40,000	40,000
Fair value of plan assets at end of year	516,089	484,408	$ 449,960
Funded status of the plan recognized as a non-current liability	(72,422)	(28,998)
Amounts recognized in accumulated other comprehensive income:
Unrecognized net actuarial losses	235,747	185,819
Unamortized prior service credits	(2,903)	(4,476)
Amount recognized in accumulated other comprehensive income	232,844	181,343
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net actuarial gain	62,659	40,723
Amortization of net actuarial losses	(12,731)	(13,007)
Amortization of prior service credits	1,573	1,573
Other changes in plan assets and benefit obligations recognized in other comprehensive income	$ 51,501	$ 29,289
Weighted average assumptions used to calculate actuarial present values of benefit obligations
Discount rate	3.40%	4.30%
Weighted average assumptions used to determine net benefit costs
Discount rate	4.30%	4.00%
Expected return on plan assets	8.30%	8.50%