Pension and retirement plans (Tables)

9 Months Ended

Apr. 01, 2017

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

Components of net periodic pension costs

	Third Quarters Ended				Nine Months Ended
	April 1,		April 2,		April 1,		April 2,
	2017		2016		2017		2016
	(Thousands)
Service cost	$	7,406	$	9,935	$	22,217	$	30,356
Interest cost		3,952		5,328		11,856		15,984
Expected return on plan assets		(10,840)		(10,071)		(32,520)		(30,213)
Amortization of prior service credits		3,610		3,183		10,830		9,549
Recognized net actuarial loss		(394)		(393)		(1,180)		(1,179)
Net periodic pension cost	$	3,734	$	7,982	$	11,203	$	24,497