Retirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015
Domestic Plans
Net periodic benefit cost:
Service cost	$ 315	$ 331	$ 631	$ 662
Interest cost	827	806	1,654	1,612
Expected return on assets	(854)	(973)	(1,708)	(1,946)
Prior service costs (credits)	3	3	6	6
Cumulative actuarial net loss (gains)	20	104	41	208
Net periodic benefit cost	311	271	624	542
Foreign Plans
Net periodic benefit cost:
Service cost	643	649	1,263	1,290
Interest cost	798	802	1,568	1,593
Expected return on assets	(863)	(952)	(1,695)	(1,890)
Prior service costs (credits)	6	5	11	11
Cumulative actuarial net loss (gains)	50	60	99	119
Net periodic benefit cost	634	564	1,246	1,123
OPEB Plans
Net periodic benefit cost:
Service cost	3	2	6	6
Interest cost	32	44	63	87
Expected return on assets	0	0	0	0
Prior service costs (credits)	(2)	(2)	(4)	(4)
Cumulative actuarial net loss (gains)	(46)	(5)	(91)	(10)
Net periodic benefit cost	$ (13)	$ 39	$ (26)	$ 79