Supplementary Quarterly Financial Information (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2011
Supplementary Quarterly Financial Information [Abstract]
Net sales	$ 102,010	$ 98,351	$ 94,590	$ 91,237	$ 93,936	$ 91,631	$ 85,001	$ 81,520	$ 386,189	$ 352,089	$ 339,426
Gross margin	23,781	22,839	22,747	21,101	23,759	22,098	20,458	18,964	90,469	85,279	77,302
Net income (1)	$ 4,240	$ 3,118	$ 2,922	$ 2,872	$ 4,399	$ 3,343	$ 2,948	$ 2,378	$ 13,151	$ 13,068	$ 10,417
Earnings per share: Basic	$ 0.60	$ 0.44	$ 0.42	$ 0.41	$ 0.64	$ 0.49	$ 0.44	$ 0.35	$ 1.87	$ 1.93	$ 1.56
Earnings per share: Diluted	$ 0.57	$ 0.42	$ 0.40	$ 0.40	$ 0.61	$ 0.48	$ 0.42	$ 0.34	$ 1.80	$ 1.86	$ 1.50