Net Income per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Net Income per Common Share [Abstract]
Net income	$ 18,257	$ 25,603	$ 42,549	$ 49,286
Basic weighted-average shares outstanding	34,231,000	40,755,000	36,204,000	41,740,000
Dilutive effect of stock-based awards	808,000	760,000	873,000	819,000
Diluted weighted-average shares outstanding	35,039,000	41,515,000	37,077,000	42,559,000
Net income per share – basic (in USD per share)	$ 0.53	$ 0.63	$ 1.18	$ 1.18
Net income per share – diluted (in USD per share)	$ 0.52	$ 0.62	$ 1.15	$ 1.16