Net Income Per Common Share - Calculation of EPS and Reconciliation of Weighted Average Common Shares Used in Calculation of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Earnings Per Share [Abstract]
Net income	$ 22,548	$ 10,255	$ 29,888	$ 13,254
Weighted-average common shares - Basic	50,317	49,473	50,087	49,368
Add: Dilutive effect of stock compensation plans	1,739	2,191	1,936	2,239
Weighted-average common shares - Diluted	52,056	51,664	52,023	51,607
Net income per common share:
Basic	$ 0.45	$ 0.21	$ 0.60	$ 0.27
Diluted	$ 0.43	$ 0.20	$ 0.57	$ 0.26