Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (10,820)	$ (1,749)	$ (26,968)	$ (7,082)
Other comprehensive income, net of tax:
Foreign currency translation adjustments	4,635	2,132	1,763	(280)
Adjustments related to postretirement benefits	18	33	108	109
Change in unrealized gain/loss on investments	(3)	13	(10)	12
Other comprehensive income (loss), net of tax	4,650	2,178	1,861	(159)
Comprehensive income (loss)	$ (6,170)	$ 429	$ (25,107)	$ (7,241)