Consolidated Statements of Stockholders Equity (USD $) In Thousands	Total	Common Stock $1 Par Value [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 25, 2010	$ 274,725	$ 23,989	$ 71,799	$ 179,134	$ (197)
Net income (loss)	15,719			15,719
Changes in cumulative translation adjustment	(1,076)				(1,076)
Adjustments related to postretirement benefits, net of income taxes	1,267				1,267
Changes in unrealized gains and losses on investments, net of income taxes	(6)				(6)
Cash dividends - $0.24 per share	(5,798)			(5,798)
Exercise of stock options	1,111	123	988
Shares issued under employee stock purchase plan	1,262	120	1,142
Shares issued for restricted stock units vested		139	(139)
Repurchase and retirement of stock	(462)	(41)	(421)
Share-based compensation expense	4,287		4,287
Tax benefit from equity awards	2		2
Ending balance at Dec. 31, 2011	291,031	24,330	77,658	189,055	(12)
Net income (loss)	(12,243)			(12,243)
Changes in cumulative translation adjustment	1,689				1,689
Adjustments related to postretirement benefits, net of income taxes	122				122
Changes in unrealized gains and losses on investments, net of income taxes	(16)				(16)
Cash dividends - $0.24 per share	(5,875)			(5,875)
Exercise of stock options	609	73	536
Shares issued under employee stock purchase plan	1,252	152	1,100
Shares issued for restricted stock units vested		108	(108)
Repurchase and retirement of stock	(291)	(31)	(260)
Share-based compensation expense	4,621		4,621
Ending balance at Dec. 29, 2012	280,899	24,632	83,547	170,937	1,783
Net income (loss)	(33,418)			(33,418)
Changes in cumulative translation adjustment	3,270				3,270
Adjustments related to postretirement benefits, net of income taxes	1,604				1,604
Changes in unrealized gains and losses on investments, net of income taxes	(6)				(6)
Cash dividends - $0.24 per share	(5,973)			(5,973)
Exercise of stock options	886	117	769
Shares issued under employee stock purchase plan	1,251	163	1,088
Shares issued for restricted stock units vested		249	(249)
Repurchase and retirement of stock	(821)	(81)	(740)
Share-based compensation expense	5,468		5,468
Ending balance at Dec. 28, 2013	$ 253,160	$ 25,080	$ 89,883	$ 131,546	$ 6,651