Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified		Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2011		$ 216	$ 174,375	$ (58,834)	$ 8,631	$ 376,572	$ 143	$ 501,103
Comprehensive income:
Net income for the year						75,332		75,332
Pension liability adjustments	[1]				(7,301)			(7,301)
Unrealized gain on investments	[1]				1,225			1,225
Foreign currency translation adjustments					13,993			13,993
Comprehensive income								83,249
Stock-based compensation			7,348					7,348
Withheld				(1,662)				(1,662)
Stock options exercised		4	14,080					14,084
Cash dividends paid						(16,564)		(16,564)
Balance at Dec. 29, 2012		220	195,803	(60,496)	16,548	435,340	143	587,558
Comprehensive income:
Net income for the year						88,784		88,784
Pension liability adjustments	[1]				3,739			3,739	[2]
Unrealized gain on investments	[1]				1,526			1,526	[3]
Foreign currency translation adjustments					(1,396)			(1,396)
Comprehensive income								92,653
Stock-based compensation			8,609					8,609
Withheld				(2,200)				(2,200)
Retirement of 1,576,757 shares of treasury shares				60,343		(60,343)
Stock options exercised		5	19,013					19,018
Cash dividends paid						(18,722)		(18,722)
Balance at Dec. 28, 2013		225	223,425	(2,353)	20,417	445,059	143	686,916
Comprehensive income:
Net income for the year						99,418		99,418
Pension liability adjustments	[1]				(12,475)			(12,475)	[2]
Unrealized gain on investments	[1]				1,398			1,398	[3]
Foreign currency translation adjustments					(30,466)			(30,466)
Comprehensive income								57,875
Stock-based compensation			6,926					6,926
Withheld				(2,655)				(2,655)
Purchase of 161,751 shares of common stock		(2)	(565)	(13,716)				(14,283)
Stock options exercised		3	14,058					14,061
Cash dividends paid						(21,175)		(21,175)
Balance at Dec. 27, 2014		$ 226	$ 243,844	$ (18,724)	$ (21,126)	$ 523,302	$ 143	$ 727,665

[1] Including related tax impact (see Note 14).

[2] Net of tax of $12,587, $6,549, and $11,819 for 2014, 2013 and 2012, respectively.

[3] Net of tax of $0, $0 and $0 for 2014, 2013 and 2012, respectively.