Pension Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2015	Mar. 30, 2014
Compensation and Retirement Disclosure [Abstract]
Service cost	$ 304	$ 282
Interest cost	535	916
Expected return on plan assets	(34)	0
Amortization of actuarial loss	750	385
Amortization of prior service costs	6	3
Net periodic pension cost	1,561	$ 1,586
Estimated employer contributions	4,200
Pension contributions	$ 1,200