Product Warranties - Additional Information (Detail)	6 Months Ended
	Jan. 31, 2013
Product Warranty [Line Items]
Product warranty period	1 year
Minimum [Member]
Product Warranty [Line Items]
Cost of satisfying warranty claims	0.60%
Maximum [Member]
Product Warranty [Line Items]
Cost of satisfying warranty claims	2.40%
Cortelco Products [Member] | Minimum [Member]
Product Warranty [Line Items]
Product warranty period	1 year
Cortelco Products [Member] | Maximum [Member]
Product Warranty [Line Items]
Product warranty period	5 years