Pension and retirement plans (Fair Value) (Details) (Pension Plans, Defined Benefit [Member], USD $) In Thousands, unless otherwise specified	Jun. 28, 2014	Jun. 29, 2013	Jun. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 449,960	$ 365,373	$ 301,449
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,025	3,032
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,025	3,032
Fair Value, Inputs, Level 1 [Member] | U.S. common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 1 [Member] | International common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 1 [Member] | U.S. government agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 1 [Member] | U.S. corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	446,935	362,341
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | U.S. common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	267,741	219,225
Fair Value, Inputs, Level 2 [Member] | International common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71,273	56,458
Fair Value, Inputs, Level 2 [Member] | U.S. government agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,439	10,004
Fair Value, Inputs, Level 2 [Member] | U.S. corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	97,482	76,654
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | U.S. common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | International common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | U.S. government agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | U.S. corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	449,960	365,373
Estimate of Fair Value, Fair Value Disclosure [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,025	3,032
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	267,741	219,225
Estimate of Fair Value, Fair Value Disclosure [Member] | International common stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71,273	56,458
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,439	10,004
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 97,482	$ 76,654