Information as to Operating Segments and Foreign and Domestic Operations (Details 3) (USD $)	3 Months Ended								12 Months Ended
	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Information as to geographic areas
Net sales	$ 113,973,000	$ 105,009,000	$ 106,363,000	$ 99,681,000	$ 98,693,000	$ 97,238,000	$ 97,297,000	$ 93,262,000	$ 425,026,000	$ 386,490,000	$ 321,651,000
Total long-lived assets	49,464,000				45,954,000				49,464,000	45,954,000	36,158,000
Goodwill and intangible assets, net	287,547,000				254,966,000				287,547,000	254,966,000	173,961,000
Total	337,011,000				300,920,000				337,011,000	300,920,000	210,119,000
United States
Information as to geographic areas
Net sales									357,378,000	329,261,000	270,341,000
Total long-lived assets	47,043,000				43,353,000				47,043,000	43,353,000	33,477,000
Canada
Information as to geographic areas
Net sales									18,732,000	15,646,000	15,635,000
Total long-lived assets	1,236,000				1,365,000				1,236,000	1,365,000	1,689,000
Asia/Pacific
Information as to geographic areas
Net sales									21,895,000	16,323,000	14,551,000
Total long-lived assets	1,030,000				1,130,000				1,030,000	1,130,000	905,000
Europe
Information as to geographic areas
Total long-lived assets	155,000				106,000				155,000	106,000	87,000
Europe/Africa/Middle East
Information as to geographic areas
Net sales									23,415,000	21,691,000	17,608,000
Latin America/South America
Information as to geographic areas
Net sales									$ 3,606,000	$ 3,569,000	$ 3,516,000