Pension and retirement plans (Tables)

9 Months Ended

Apr. 02, 2016

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Components of net periodic pension costs

	Third Quarters Ended				Nine Months Ended
	April 2,		March 28,		April 2,		March 28,
	2016		2015		2016		2015
	(Thousands)
Service cost	$	9,935	$	9,873	$	30,356	$	29,619
Interest cost		5,328		4,449		15,984		13,347
Expected return on plan assets		(10,071)		(9,055)		(30,213)		(27,165)
Recognized net actuarial loss		3,183		3,251		9,549		9,753
Amortization of prior service credits		(393)		(393)		(1,179)		(1,179)
Net periodic pension cost	$	7,982	$	8,125	$	24,497	$	24,375