Pension and retirement plans (Fair Value) (Details) - USD ($) $ in Thousands	Jul. 01, 2017	Jul. 02, 2016	Jun. 27, 2015
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 699,365	$ 516,089	$ 484,408
Estimate of Fair Value Measurement
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	699,365
Estimate of Fair Value Measurement | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		516,089
Estimate of Fair Value Measurement | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,481
Estimate of Fair Value Measurement | Cash and cash equivalents | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		497
Estimate of Fair Value Measurement | U.S. common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221,003
Estimate of Fair Value Measurement | U.S. common stocks [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		204,125
Estimate of Fair Value Measurement | International common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117,392
Estimate of Fair Value Measurement | International common stocks [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		102,193
Estimate of Fair Value Measurement | U.S. government agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	105,227
Estimate of Fair Value Measurement | U.S. government agencies [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		76,991
Estimate of Fair Value Measurement | Foreign Government Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,366
Estimate of Fair Value Measurement | U.S. corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	214,024
Estimate of Fair Value Measurement | U.S. corporate bonds [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		112,262
Estimate of Fair Value Measurement | Other Debt Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25,872
Estimate of Fair Value Measurement | Other Debt Obligations [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		20,021
Level 1 | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,481	497
Level 1 | Cash and cash equivalents | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,481	497
Level 2 | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	697,884	515,592
Level 2 | U.S. common stocks [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221,003	204,125
Level 2 | International common stocks [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117,392	102,193
Level 2 | U.S. government agencies [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	105,227	76,991
Level 2 | Foreign Government Debt Securities [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,366
Level 2 | U.S. corporate bonds [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	214,024	112,262
Level 2 | Other Debt Obligations [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 25,872	$ 20,021