| 
           Deferred contract costs (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Sep. 30, 2014 
         | 
        
           Sep. 30, 2013 
         | 
      
|---|---|---|
| Deferred contract costs | ||
| Deferred contract costs | $ 25,489 | $ 23,623 | 
| Less: accumulated amortization | (13,443) | (9,305) | 
| Total deferred contract costs, net | $ 12,046 | $ 14,318 | 
| X | ||||||||||
| 
             
- Definition 
          Accumulated amortization of deferred contract costs capitalized at the end of the reporting period. No definition available. 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Deferred incremental direct costs incurred typically at a contract's inception so that the company may be in a position to fulfill all contractual obligations of an arrangement. The costs are directly related to specified activities under the arrangement and are deferred in order to match revenue. Excludes start-up costs (such as one-time activities related to opening a new facility, introducing a new product or service, establishing business with a new class of customers, preopening costs, and organization costs), which are expensed as incurred. No definition available. 
  | 
        
| X | ||||||||||
| 
             
- Details 
          
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Deferred incremental direct costs before deducting accumulated amortization, which are incurred typically at a contract's inception so that the company may be in a position to fulfill all contractual obligations of an arrangement. The costs are directly related to specified activities under the arrangement and are deferred in order to match revenue. Excludes start-up costs (such as one-time activities related to opening a new facility, introducing a new product or service, establishing business with a new class of customers, preopening costs and organization costs), which are expensed as incurred. No definition available. 
  |