Intangible Assets (Details) - USD ($) |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jan. 31, 2016 |
Jan. 31, 2015 |
Jan. 31, 2016 |
Jan. 31, 2015 |
Jul. 31, 2015 |
|
| Finite-Lived Intangible Assets [Line Items] | |||||
| Gross carrying amount | $ 82,995,000 | $ 82,995,000 | $ 82,995,000 | ||
| Accumulated amortization | 65,558,000 | 65,558,000 | 62,986,000 | ||
| Net carrying amount | 17,437,000 | 17,437,000 | $ 20,009,000 | ||
| Amortization of intangibles | 1,196,000 | $ 1,560,000 | 2,572,000 | $ 3,121,000 | |
| Amortization expense - year one | 4,962,000 | 4,962,000 | |||
| Amortization expense - year two | 4,782,000 | 4,782,000 | |||
| Amortization expense - year three | 4,782,000 | 4,782,000 | |||
| Amortization expense - year four | 862,000 | 862,000 | |||
| Amortization expense - year five | 862,000 | $ 862,000 | |||
| Technologies | |||||
| Finite-Lived Intangible Assets [Line Items] | |||||
| Weighted average amortization period | 13 years | 12 years 1 month 6 days | |||
| Gross carrying amount | 47,370,000 | $ 47,370,000 | $ 47,370,000 | ||
| Accumulated amortization | 40,245,000 | 40,245,000 | 39,266,000 | ||
| Net carrying amount | 7,125,000 | $ 7,125,000 | $ 8,104,000 | ||
| Customer relationships | |||||
| Finite-Lived Intangible Assets [Line Items] | |||||
| Weighted average amortization period | 10 years | 10 years | |||
| Gross carrying amount | 29,831,000 | $ 29,831,000 | $ 29,831,000 | ||
| Accumulated amortization | 22,456,000 | 22,456,000 | 20,981,000 | ||
| Net carrying amount | 7,375,000 | $ 7,375,000 | $ 8,850,000 | ||
| Trademarks and other | |||||
| Finite-Lived Intangible Assets [Line Items] | |||||
| Weighted average amortization period | 20 years | 20 years | |||
| Gross carrying amount | 5,794,000 | $ 5,794,000 | $ 5,794,000 | ||
| Accumulated amortization | 2,857,000 | 2,857,000 | 2,739,000 | ||
| Net carrying amount | $ 2,937,000 | $ 2,937,000 | $ 3,055,000 | ||