Accumulated Other Comprehensive Earnings (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 29, 2013	Mar. 31, 2013	Jun. 30, 2012	Mar. 31, 2012	Jun. 29, 2013	Jun. 30, 2012
Foreign Currency Translation
Balance at beginning of period	$ (12,265)	$ (13,406)	$ (12,880)	$ (14,686)	$ (13,406)	$ (14,686)
Other comprehensive earnings (loss) before reclassifications on foreign currency translation	(1,223)	1,122	(1,510)	1,851
Net other comprehensive earnings (loss) before tax	(1,223)	1,122	(1,510)	1,851	(101)	341
Income tax benefit (expense)	(8)	19	71	(45)
Balance at end of period	(13,496)	(12,265)	(14,319)	(12,880)	(13,496)	(14,319)
Investments
Balance at beginning of period	417	908	(703)	(351)	908	(351)
Other comprehensive earnings (loss) before reclassifications	589	(770)	514	(546)	(181)	(32)
Net other comprehensive earnings (loss) before tax	589	(770)	514	(546)	(181)	(32)
Income tax benefit (expense)	(213)	279	(186)	194
Balance at end of period	793	417	(375)	(703)	793	(375)
Foreign Currency Derivatives
Balance at beginning of period	(158)		195	129		129
Other comprehensive earnings (loss) before reclassifications on foreign currency derivatives	(585)	(282)	(124)	252
Reclassifications from accumulated other comprehensive loss	73	35	(115)	(149)
Net other comprehensive earnings (loss) before tax	(512)	(247)	(239)	103
Income tax benefit (expense)	186	89	88	(37)
Balance at end of period	(484)	(158)	44	195	(484)	44
Commodity Derivatives
Balance at beginning of period	(320)	(111)	280	128	(111)	128
Other comprehensive earnings (loss) before reclassifications on commodity derivatives	(217)	(648)	(575)	254
Reclassifications from accumulated other comprehensive loss	473	320		(18)
Net other comprehensive earnings (loss) before tax	256	(328)	(575)	236
Income tax benefit (expense)	(93)	119	208	(84)
Balance at end of period	(157)	(320)	(87)	280	(157)	(87)
Postretirement and Pension Benefits
Balance at beginning of period	(3,838)	(3,838)	(5,173)	(5,173)	(3,838)	(5,173)
Balance at end of period	(3,838)	(3,838)	(5,173)	(5,173)	(3,838)	(5,173)
Accumulated Other Comprehensive Earnings (Loss)
Balance at beginning of period	(16,164)	(16,447)	(18,281)	(19,953)	(16,447)	(19,953)
Other comprehensive earnings (loss) before reclassifications on postretirement and pension benefits	(1,436)	(578)	(1,695)	1,811
Reclassifications from accumulated other comprehensive loss	546	355	(115)	(167)
Net other comprehensive earnings (loss) before tax	(890)	(223)	(1,810)	1,644	(1,113)	(166)
Income tax benefit (expense)	(128)	506	181	28	378	209
Balance at end of period	$ (17,182)	$ (16,164)	$ (19,910)	$ (18,281)	$ (17,182)	$ (19,910)