Quarterly Result of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Sales	$ 91,698	$ 79,600	$ 78,538	$ 75,748	$ 91,327	$ 72,507	$ 83,775	$ 69,939	$ 325,584	$ 317,548	$ 341,826
Segment profit	48,677	42,678	43,934	42,671	48,523	34,766	44,441	39,506	177,960	167,236	188,510
Net income	$ 3,545	$ 1,090	$ 3,392	$ 3,080	$ 8,885	$ (884)	$ 4,148	$ 664	$ 11,107	$ 12,813	$ 33,649
Net income per share:
Basic EPS (in dollars per share)	$ 0.21	$ 0.07	$ 0.20	$ 0.19	$ 0.52	$ (0.05)	$ 0.24	$ 0.04	$ 0.67	$ 0.74	$ 1.95
Diluted EPS (in dollars per share)	$ 0.21	$ 0.07	$ 0.20	$ 0.19	$ 0.52	$ (0.05)	$ 0.24	$ 0.04	$ 0.67	$ 0.74	$ 1.93