Goodwill (Details) (USD $)
9 Months Ended
Apr. 30, 2011
Jul. 31, 2010
Goodwill Gross $ 150,603,000 $ 150,603,000
Goodwill Accumulated Impairment (13,249,000) (13,249,000)
Goodwill 137,354,000 137,354,000
Number of reportable operating segments 3  
Telecommunications Transmission [Member]
   
Goodwill Gross 107,779,000 107,779,000
Goodwill Accumulated Impairment 0 0
Goodwill 107,779,000 107,779,000
Mobile Data Communications [Member]
   
Goodwill Gross 13,249,000 13,249,000
Goodwill Accumulated Impairment (13,249,000) (13,249,000)
Goodwill 0 0
R F Microwave Amplifiers [Member]
   
Goodwill Gross 29,575,000 29,575,000
Goodwill Accumulated Impairment 0 0
Goodwill $ 29,575,000 $ 29,575,000