Employee Benefit Plans (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2011	Oct. 02, 2010	Oct. 01, 2011	Oct. 02, 2010
Components of net periodic benefit costs:
Service cost	$ 381	$ 411	$ 1,143	$ 1,233
Interest cost	2,274	2,248	6,822	6,744
Expected return on plan assets	(1,656)	(1,498)	(4,968)	(4,494)
Amortization of unrecognized net loss	858	967	2,574	2,901
Amortization of prior service cost	11	20	33	60
Amortization of transition obligation	0	7	0	21
Net periodic benefit costs	$ 1,868	$ 2,155	$ 5,604	$ 6,465