Retirement Plans - Net Pension Income Domestic and Foreign (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 29, 2015
Pension Plans
Net pension expense (income)
(Income) expense, net	$ (392)	$ (528)
Domestic Pension Plans
Net pension expense (income)
Service cost	22	42
Interest cost	2,756	2,815
Expected return on plan assets	(4,744)	(5,068)
Amortization of loss	1,498	1,585
Other cost due to retirement	12	0
(Income) expense, net	(456)	(626)
Foreign Pension Plans
Net pension expense (income)
Service cost	12	17
Interest cost	11	123
Expected return on plan assets	7	(133)
Amortization of loss	34	91
Other cost due to retirement	0	0
(Income) expense, net	$ 64	$ 98