Pension and retirement plans (Fair Value) (Details) - USD ($) $ in Thousands	Jun. 27, 2026	Jun. 28, 2025	Jun. 29, 2024
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 484,068	$ 477,558	$ 480,705
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,661	17,880
Common Stocks
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	151,184	147,890
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	78,515	74,747
High yield credit and bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	83,745	84,857
U.S. government agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113,482	113,401
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34,481	38,783
Level 1 \| Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,661	17,880
Level 1 \| Recurring \| Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,661	17,880
Net Asset Value \| Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	461,407	459,678
Net Asset Value \| Recurring \| Common Stocks
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	151,184	147,890
Net Asset Value \| Recurring \| Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	78,515	74,747
Net Asset Value \| Recurring \| High yield credit and bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	83,745	84,857
Net Asset Value \| Recurring \| U.S. government agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113,482	113,401
Net Asset Value \| Recurring \| Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 34,481	$ 38,783