Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 940	$ 434	$ 1,354	$ 1,185
Foreign currency translation adjustment, net of taxes	(1,829)	1,215	(1,149)	1,479
Change in pension loss, net of taxes of $9 and $15 in the 2018 and 2017 second quarters, respectively, and $18 and $29 in the first two quarters of 2018 and 2017, respectively	503	(445)	270	(513)
Other comprehensive income (loss)	(1,326)	770	(879)	966
Comprehensive income (loss)	$ (386)	$ 1,204	$ 475	$ 2,151