Statements of Comprehensive Income (Unaudited) (USD $)
 3 Months Ended 9 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Mar. 31, 2014
Mar. 31, 2013
Income Statement [Abstract]        
Net sales $ 6,549,623 $ 6,799,970 $ 20,040,219 $ 22,744,294
Cost of sales 4,870,498 4,830,092 15,269,944 16,147,715
Gross profit 1,679,125 1,969,878 4,770,275 6,596,579
Selling, general and administrative expenses 762,329 725,596 2,316,864 2,135,293
Operating income 916,796 1,244,282 2,453,411 4,461,286
Other income        
Interest and dividend income 10,231 7,301 30,646 25,716
Other 49,717 15,322 95,854 29,827
[NonoperatingIncomeExpense] 59,948 22,623 126,500 55,543
Income before income taxes 976,744 1,266,905 2,579,911 4,516,829
Provision for income taxes 270,714 351,674 713,822 1,249,104
Net income 706,030 915,231 1,866,089 3,267,725
Other comprehensive income, net of tax:        
Unrealized (loss) gain on investment securities (569) (5) (919) 1,700
Total comprehensive income $ 705,461 $ 915,226 $ 1,865,170 $ 3,269,425
Net income per share:        
Basic $ 0.31 $ 0.41 $ 0.83 $ 1.48
Diluted $ 0.31 $ 0.41 $ 0.82 $ 1.46
Weighted average number of shares outstanding:        
Basic 2,249,175 2,217,641 2,240,834 2,201,619
Diluted 2,294,616 2,247,599 2,285,904 2,240,181
Dividends per share $ 0.25 $ 0.25 $ 1.75 $ 1.725