Supplemental Quarterly Financial Data (Unaudited) - (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net Revenues	$ 186,926	$ 181,101	$ 180,495	$ 172,566	$ 164,183	$ 159,842	$ 154,827	$ 150,455	$ 721,088	$ 629,307	$ 558,183
Gross Profit	40,111	38,327	38,065	35,694	32,697	31,116	32,028	26,755	152,197	122,596	103,133
Income Before Taxes	9,848	10,240	9,178	8,497	1,791	4,290	1,833	2,357	37,763	10,271	7,609
Income Tax Expense (Benefit)	977	1,937	1,363	1,025	1,118	119	242	(243)	5,302	1,236	(12,468)
Net Income	$ 8,871	$ 8,303	$ 7,815	$ 7,472	$ 673	$ 4,171	$ 1,591	$ 2,600	$ 32,461	$ 9,035	$ 20,077
Earnings Per Share
Basic earnings (loss) per share (in dollars per share)	$ 0.77	$ 0.72	$ 0.68	$ 0.65	$ 0.06	$ 0.37	$ 0.14	$ 0.23	$ 2.82	$ 0.79	$ 1.78
Diluted earnings (loss) per share (in dollars per share)	$ 0.75	$ 0.70	$ 0.66	$ 0.64	$ 0.06	$ 0.36	$ 0.14	$ 0.22	$ 2.75	$ 0.77	$ 1.74