Income Taxes (Details 3) (USD $)	12 Months Ended
Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Income tax reconciliation disclosure
United States statutory tax rate (as a percent)	35.00%	35.00%	35.00%
Expected statutory tax	$ 21,124,000	$ 16,754,000	$ 10,662,000
State and local taxes	2,044,000	1,434,000	867,000
Domestic production deduction	(1,265,000)	(1,009,000)	(657,000)
Taxes on foreign dividends	120,000	(72,000)	(241,000)
R&E tax credit	(492,000)	(138,000)	(346,000)
Investment impairment		175,000
Other	306,000	372,000	242,000
Total income tax expense	21,115,000	16,532,000	10,037,000
Canada
Income tax reconciliation disclosure
Differential attributable to foreign operations:	49,000	54,000	(225,000)
Singapore
Income tax reconciliation disclosure
Differential attributable to foreign operations:	(224,000)	(161,000)	(142,000)
Netherlands
Income tax reconciliation disclosure
Differential attributable to foreign operations:	(546,000)	(53,000)	(50,000)
Japan
Income tax reconciliation disclosure
Differential attributable to foreign operations:	$ (1,000)	$ (824,000)	$ (73,000)

The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to the deduction for dividends paid or received under enacted tax laws.

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