Retirement Plans - (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Domestic Plans
Net periodic benefit cost:
Service cost	$ 323	$ 268	$ 645	$ 535
Interest cost	788	721	1,576	1,442
Expected return on plan assets	(1,018)	(887)	(2,036)	(1,774)
Net periodic benefit cost	96	151	191	301
Prior service cost	3	0	6	0
Cumulative actuarial net loss	0	49	0	98
Foreign Plans
Net periodic benefit cost:
Service cost	606	704	1,197	1,421
Interest cost	924	945	1,827	1,907
Expected return on plan assets	(1,095)	(979)	(2,164)	(1,976)
Net periodic benefit cost	454	806	898	1,626
Prior service cost	5	5	10	10
Cumulative actuarial net loss	14	131	28	264
OPEB Plans
Net periodic benefit cost:
Service cost	3	3	6	7
Interest cost	49	49	98	99
Expected return on plan assets	0	0	0	0
Net periodic benefit cost	39	54	78	110
Prior service cost	(2)	0	(4)	0
Cumulative actuarial net loss	$ (11)	$ 2	$ (22)	$ 4