Employee Retirement Plans (Tables)

9 Months Ended

Sep. 26, 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				Nine Months Ended
	Sep 26, 2020		Sep 28, 2019		Sep 26, 2020		Sep 28, 2019
Net Periodic Pension Benefit:
Service cost	$	649	$	593	$	1,918	$	1,839
Interest cost	6,456		7,995		19,086		24,776
Expected return on assets	(18,089)		(16,118)		(53,476)		(49,948)
Amortization of net loss (gain)	842		149		2,489		462
Amortization of prior service cost (credit)	642		614		1,897		1,904
Curtailment loss (gain)	—		185		—		573
	$	(9,500)	$	(6,582)	$	(28,086)	$	(20,394)