CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (12,103)	$ (3,224)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(4,002)	2,583
Adjustments related to postretirement benefits	59	32
Change in unrealized gain/loss on investments	(3)	12
Other comprehensive income (loss), net of tax	(3,946)	2,627
Comprehensive income (loss)	$ (16,049)	$ (597)