Net Income per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Net Income per Common Share [Abstract]
Net income	$ 20,548	$ 24,461
Basic weighted-average shares outstanding	38,244,000	42,750,000
Dilutive effect of stock-based awards	1,103,000	962,000
Diluted weighted-average shares outstanding	39,347,000	43,712,000
Net income per share – basic (in USD per share)	$ 0.54	$ 0.57
Net income per share – diluted (in USD per share)	$ 0.52	$ 0.56