Pensions and Other Post-employment Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2012	Apr. 01, 2011
Pension Benefits [Member]
Components of net periodic benefit cost
Service cost	$ 1,932	$ 1,516
Interest cost	2,336	2,309
Expected return on plan assets	(2,926)	(2,685)
Amortization of prior service cost (benefit)	(84)	(118)
Amortization of net loss	1,402	982
Net periodic benefit cost	2,660	2,004
Other Benefits [Member]
Components of net periodic benefit cost
Service cost	71	71
Interest cost	360	399
Amortization of prior service cost (benefit)	22	(9)
Net periodic benefit cost	$ 453	$ 461