Income Taxes (Details 2) (USD $)	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Geographic components of income before income taxes
Income before income taxes	$ 60,354,000	$ 47,869,000	$ 30,462,000
United States
Geographic components of income before income taxes
Income before income taxes	57,973,000	44,120,000	27,772,000
Canada
Geographic components of income before income taxes
Income before income taxes	(5,000)	531,000	1,532,000
Singapore
Geographic components of income before income taxes
Income before income taxes	1,038,000	713,000	796,000
Netherlands
Geographic components of income before income taxes
Income before income taxes	1,344,000	152,000	143,000
Japan
Geographic components of income before income taxes
Income before income taxes	$ 4,000	$ 2,353,000	$ 219,000