Supplemental Quarterly Financial Data (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net Revenues	$ 164,183	$ 159,842	$ 154,827	$ 150,455	$ 142,258	$ 138,690	$ 140,938	$ 136,297	$ 629,307	$ 558,183	$ 550,642
Gross Profit	32,697	31,116	32,028	26,755	25,772	26,087	26,269	25,005	122,596	103,133	106,540
Income (Loss) Before Taxes	1,791	4,290	1,833	2,357	(5,057)	5,595	4,564	2,507	10,271	7,609	38,113
Income Tax Expense (Benefit)	1,118	119	242	(243)	(14,541)	940	741	392	1,236	(12,468)	12,852
Net Income	$ 673	$ 4,171	$ 1,591	$ 2,600	$ 9,484	$ 4,655	$ 3,823	$ 2,115	$ 9,035	$ 20,077	$ 25,261
Earnings Per Share
Basic earnings (loss) per share (in dollars per share)	$ 0.06	$ 0.37	$ 0.14	$ 0.23	$ 0.84	$ 0.41	$ 0.34	$ 0.19	$ 0.79	$ 1.78	$ 2.27
Diluted earnings (loss) per share (in dollars per share)	$ 0.06	$ 0.36	$ 0.14	$ 0.22	$ 0.82	$ 0.41	$ 0.33	$ 0.18	$ 0.77	$ 1.74	$ 2.24