Pension Benefits (Details) - USD ($) $ in Thousands		3 Months Ended
	Apr. 28, 2020	Mar. 31, 2020	Mar. 31, 2019
Components of Net Periodic Benefit Costs for the Pension Plans
Service cost		$ 1,395	$ 1,683
Interest cost		698	656
Expected return on plan assets that reduces periodic pension benefit cost		(393)	(466)
Amortization of prior service cost		4	4
Amortization of net actuarial loss		240	332
Net periodic benefit cost		$ 1,944	$ 2,209
Pension plans, net gain (loss) amortization threshold		10.00%
Subsequent Event [Member]
Components of Net Periodic Benefit Costs for the Pension Plans
Employer contributions	$ 3,300