Employee Retirement Plans (Tables)

6 Months Ended

Jun. 27, 2020

Employee Retirement Plans [Abstract]

Schedule of Costs of Retirement Plans [Table Text Block]

The following table summarizes the company's net periodic pension benefit related to the AGA Group pension plans (in thousands):

	Three Months Ended				Six Months Ended
	Jun 27, 2020		Jun 29, 2019		Jun 27, 2020		Jun 29, 2019
Net Periodic Pension Benefit:
Service cost	$	624	$	620	$	1,269	$	1,246
Interest cost	6,212		8,349		12,630		16,781
Expected return on assets	(17,405)		(16,832)		(35,387)		(33,830)
Amortization of net (gain) loss	810		156		1,647		313
Amortization of prior service cost (credit)	617		642		1,255		1,290
Curtailment loss (gain)	—		388		—		388
	$	(9,142)	$	(6,677)	$	(18,586)	$	(13,812)