Pension and Other Postretirement Obligations (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Oct. 02, 2011	Oct. 03, 2010	Oct. 02, 2011	Oct. 03, 2010
Pension Obligations [Member]
Components of net periodic benefit costs for our pension plans
Service cost	$ 1,473	$ 1,947	$ 4,187	$ 5,111
Interest cost	2,844	4,205	8,521	11,461
Expected return on plan assets	(2,807)	(4,337)	(8,570)	(11,635)
Amortization of prior service cost (credit)	(56)	29	(128)	49
Net loss (gain) recognition	1,447	651	4,535	2,169
Net periodic benefit cost	2,901	2,495	8,545	7,155
Other Postretirement Obligations [Member]
Components of net periodic benefit costs for our pension plans
Service cost	32	28	113	80
Interest cost	577	649	1,931	1,997
Amortization of prior service cost (credit)	(54)	(48)	(173)	(165)
Net loss (gain) recognition	124	(3)	354	141
Net periodic benefit cost	$ 679	$ 626	$ 2,225	$ 2,053