Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, Balance at December 28, 2014	$ (46,541)
Other comprehensive income (loss)	(6,335)
Accumulated Other Comprehensive Income, Balance at March 29, 2015	(52,876)
Unrecognized Benefit Plan Gains and Losses
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, Balance at December 28, 2014	(49,323)
Other comprehensive income (loss)	(5)
Accumulated Other Comprehensive Income, Balance at March 29, 2015	(49,328)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, Balance at December 28, 2014	(2,665)
Other comprehensive income (loss)	(5,391)
Accumulated Other Comprehensive Income, Balance at March 29, 2015	(8,056)
Unrealized Holding Gains on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, Balance at December 28, 2014	5,447
Other comprehensive income (loss)	(939)
Accumulated Other Comprehensive Income, Balance at March 29, 2015	$ 4,508