QUARTERLY FINANCIAL REPORTING (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jun. 30, 2017	Apr. 02, 2017	Jan. 01, 2017	Oct. 02, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
QUARTERLY FINANCIAL REPORTING (UNAUDITED)
Net sales	$ 95,430	$ 93,811	$ 78,435	$ 65,049	$ 58,325	$ 58,486	$ 51,134	$ 60,689	$ 332,725	$ 228,634	$ 221,600
Gross profit	27,885	24,382	19,934	18,163	16,456	14,925	14,286	17,809	90,364	63,476	61,079
Operating income	18,938	15,199	10,782	11,064	10,559	4,282	7,039	11,635	55,983	33,515	22,011
Net income	$ 13,144	$ 11,454	$ 8,009	$ 7,046	$ 6,315	$ 2,241	$ 4,031	$ 6,983	$ 39,653	$ 19,570	$ 10,210
Basic earnings per share (in dollars per share)	$ 0.71	$ 0.62	$ 0.43	$ 0.38	$ 0.34	$ 0.12	$ 0.22	$ 0.38	$ 2.13	$ 1.05	$ 0.57
Diluted earnings per share (in dollars per share)	$ 0.70	$ 0.61	$ 0.43	$ 0.38	$ 0.34	$ 0.12	$ 0.22	$ 0.38	$ 2.12	$ 1.05	$ 0.56
Weighted average shares used for computation of:
Basic earnings per share (in shares)	18,619,834	18,622,083	18,619,834	18,615,100	18,593,501	18,593,296	18,592,936	18,591,808	18,619,793	18,592,885	17,849,319
Diluted earnings per share (in shares)	18,702,352	18,728,424	18,702,352	18,686,626	18,659,246	18,625,904	18,605,078	18,592,603	18,714,531	18,620,708	18,257,007