CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 7,519	$ (10,820)	$ 8,334	$ (26,968)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustments	(8,537)	4,635	(8,632)	1,763
Adjustments related to postretirement benefits	(92)	18	(172)	108
Change in unrealized gain/loss on investments		(3)		(10)
Other comprehensive income (loss), net of tax	(8,629)	4,650	(8,804)	1,861
Comprehensive loss	$ (1,110)	$ (6,170)	$ (470)	$ (25,107)