Quarterly Financial Information (Unaudited) - Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Gross revenues	$ 132,598	$ 131,032	$ 127,974	$ 117,335	$ 115,344	$ 104,185	$ 104,018	$ 94,534	$ 508,938	$ 418,081	$ 333,034
Gross profit	65,017	63,496	61,440	55,430	54,097	49,974	50,702	46,631	245,382	201,404	165,254
Income from operations	6,374	7,825	9,597	7,411	10,060	9,974	9,350	6,301	31,207	35,685	26,568
Income before income tax expense	5,329	7,403	9,140	7,060	9,806	9,523	8,700	5,690	28,932	33,719	24,633
Net income and comprehensive income	$ 3,575	$ 5,843	$ 8,794	$ 5,543	$ 7,659	$ 7,285	$ 7,620	$ 4,292	$ 23,756	$ 26,856	$ 24,006
Basic earnings per share (in dollars per share)	$ 0.29	$ 0.48	$ 0.73	$ 0.46	$ 0.64	$ 0.65	$ 0.73	$ 0.42	$ 1.96	$ 2.44	$ 2.36
Diluted earnings per share (in dollars per share)	$ 0.28	$ 0.46	$ 0.70	$ 0.44	$ 0.62	$ 0.62	$ 0.69	$ 0.39	$ 1.90	$ 2.33	$ 2.23