Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 30, 2016	Oct. 02, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net Income (loss)	$ (16,183)	$ 2,071	$ (35,781)	$ 3,892
Foreign currency adjustment	129	92	299	(1,456)
Change in pension loss, net of taxes of $17 and $22 in the 2016 and 2015 third quarters, respectively, and $48 and $68 in the first three quarters of 2016 and 2015, respectively	(9)	(8)	(25)	799
Other comprehensive income (loss)	120	84	274	(657)
Comprehensive income (loss)	$ (16,063)	$ 2,155	$ (35,507)	$ 3,235