Pension and retirement plans (Fair Value) (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Jun. 30, 2018	Jul. 01, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 664,063	$ 659,038	$ 699,365
Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	664,063	659,038
Recurring | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,441	7,291
Recurring | U.S. common stocks
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	254,139	262,066
Recurring | International common stocks
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	131,847	133,564
Recurring | U.S. government agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	97,015	96,414
Recurring | U.S. and international corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	153,891	133,645
Recurring | Other Debt Obligations
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,730	26,058
Level 1 | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,441	7,291
Level 1 | Recurring | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,441	7,291
Level 2 | Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	661,622	651,747
Level 2 | Recurring | U.S. common stocks
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	254,139	262,066
Level 2 | Recurring | International common stocks
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	131,847	133,564
Level 2 | Recurring | U.S. government agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	97,015	96,414
Level 2 | Recurring | U.S. and international corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	153,891	133,645
Level 2 | Recurring | Other Debt Obligations
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 24,730	$ 26,058