Intangible Assets and Goodwill - Intangible Assets Summary (Details) - USD ($)
3 Months Ended 6 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2016
Jan. 31, 2015
Jul. 31, 2015
Intangible assets with finite lives:          
Amortization expense $ 3,297,000 $ 3,232,000 $ 6,391,000 $ 6,188,000  
Gross 146,112,000   146,112,000   $ 142,539,000
Accumulated Amortization (39,763,000)   (39,763,000)   (64,855,000)
Net 106,349,000   106,349,000   77,684,000
Intangible assets with indefinite lives:          
Trademarks and tradenames 7,456,000   7,456,000   8,152,000
Total intangible assets          
Gross 153,568,000   153,568,000   150,691,000
Accumulated Amortization (39,763,000)   (39,763,000)   (64,855,000)
Net 113,805,000   $ 113,805,000   85,836,000
Minimum          
Intangible assets with finite lives:          
Estimated useful lives     3 years    
Maximum          
Intangible assets with finite lives:          
Estimated useful lives     20 years    
Weighted average          
Intangible assets with finite lives:          
Estimated useful lives     12 years    
Customer relationships          
Intangible assets with finite lives:          
Gross 101,519,000   $ 101,519,000   97,697,000
Accumulated Amortization (25,371,000)   (25,371,000)   (39,549,000)
Net 76,148,000   76,148,000   58,148,000
Total intangible assets          
Accumulated Amortization (25,371,000)   (25,371,000)   (39,549,000)
Technology          
Intangible assets with finite lives:          
Gross 32,408,000   32,408,000   26,508,000
Accumulated Amortization (10,014,000)   (10,014,000)   (12,656,000)
Net 22,394,000   22,394,000   13,852,000
Total intangible assets          
Accumulated Amortization (10,014,000)   (10,014,000)   (12,656,000)
Brand names          
Intangible assets with finite lives:          
Gross 6,739,000   6,739,000   12,970,000
Accumulated Amortization (2,457,000)   (2,457,000)   (10,865,000)
Net 4,282,000   4,282,000   2,105,000
Total intangible assets          
Accumulated Amortization (2,457,000)   (2,457,000)   (10,865,000)
Non-compete agreements          
Intangible assets with finite lives:          
Gross 3,091,000   3,091,000   3,129,000
Accumulated Amortization (1,076,000)   (1,076,000)   (997,000)
Net 2,015,000   2,015,000   2,132,000
Total intangible assets          
Accumulated Amortization (1,076,000)   (1,076,000)   (997,000)
Patents and other registrations          
Intangible assets with finite lives:          
Gross 2,355,000   2,355,000   2,235,000
Accumulated Amortization (845,000)   (845,000)   (788,000)
Net 1,510,000   1,510,000   1,447,000
Total intangible assets          
Accumulated Amortization $ (845,000)   $ (845,000)   $ (788,000)