CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2016
Jan. 31, 2015
Net sales        
Product sales $ 138,702 $ 118,350 $ 272,508 $ 238,149
Product services 19,569 17,080 39,542 34,092
Total net sales 158,271 135,430 312,050 272,241
Cost of sales        
Product sales 72,979 63,073 142,120 127,169
Product services 12,955 11,766 26,395 23,967
Total cost of sales 85,934 74,839 168,515 151,136
Gross profit 72,337 60,591 143,535 121,105
Expenses:        
Selling 22,620 19,257 44,080 38,668
General and administrative 22,252 19,822 44,449 38,329
Research and development 3,069 3,211 6,834 6,760
Total operating expenses 47,941 42,290 95,363 83,757
Income from operations 24,396 18,301 48,172 37,348
Interest expense 893 661 1,659 1,211
Interest income (22) (15) (43) (31)
Income before income taxes 23,525 17,655 46,556 36,168
Income taxes 8,136 6,570 16,913 13,844
Net income $ 15,389 $ 11,085 $ 29,643 $ 22,324
Earnings per common share:        
Basic (in dollars per share) $ 0.37 $ 0.27 $ 0.71 $ 0.54
Diluted (in dollars per share) $ 0.37 0.27 0.71 0.54
Dividends per common share (in dollars per share)   $ 0.05 $ 0.06 $ 0.05