Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Items	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2016		14,624,159			3,686,532
Beginning balance at Dec. 31, 2016	$ 284,279	$ 146	$ 101,405	$ 321,050	$ (90,335)	$ (49,637)	$ 1,650
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	31,583			31,092			491
Dividends declared - Common Stock	(9,249)			(9,249)
Dividend paid to noncontrolling interest	(882)						(882)
Activity under stock plans (in shares)					(72,694)
Activity under stock plans	3,597		1,816		$ 1,781
Other comprehensive items	23,176					22,922	254
Ending balance (in shares) at Dec. 30, 2017		14,624,159			3,613,838
Ending balance at Dec. 30, 2017	332,504	$ 146	103,221	342,893	$ (88,554)	(26,715)	1,513
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle | Accounting Standards Update 2014-09	119			119
Cumulative effect of new accounting principle | Accounting Standards Update 2016-16	(75)			(75)
Net Income	61,046			60,413			633
Dividends declared - Common Stock	(9,772)			(9,772)
Dividend paid to noncontrolling interest	(465)						(465)
Activity under stock plans (in shares)					(99,675)
Activity under stock plans	3,953		1,510		$ 2,443
Other comprehensive items	(12,739)					(12,661)	(78)
Ending balance (in shares) at Dec. 29, 2018		14,624,159			3,514,163
Ending balance at Dec. 29, 2018	374,571	$ 146	104,731	393,578	$ (86,111)	(39,376)	1,603
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle | Accounting Standards Update 2016-02	(17)			(17)
Net Income	52,564			52,068			496
Dividends declared - Common Stock	(10,380)			(10,380)
Dividend paid to noncontrolling interest	(664)						(664)
Activity under stock plans (in shares)					(299,275)
Activity under stock plans	9,300		1,967		$ 7,333
Other comprehensive items	1,705					1,756	(51)
Ending balance (in shares) at Dec. 28, 2019		14,624,159			3,214,888
Ending balance at Dec. 28, 2019	$ 427,079	$ 146	$ 106,698	$ 435,249	$ (78,778)	$ (37,620)	$ 1,384