| 
           Acquisitions (Details) 
        In Thousands, except Share data, unless otherwise specified  | 
        3 Months Ended | 9 Months Ended | 0 Months Ended | 3 Months Ended | 9 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 
           Jun. 30, 2013
 
          USD ($) 
         | 
        
           Jun. 30, 2012
 
          USD ($) 
         | 
        
           Jun. 30, 2013
 
          USD ($)
 
          segment 
         | 
        
           Jun. 30, 2012
 
          USD ($) 
         | 
        
           Jul. 02, 2013
 
          HML
 
          USD ($) 
         | 
        
           Jul. 02, 2013
 
          HML
 
          GBP (£) 
         | 
        
           Jun. 30, 2013
 
          HML
 
          USD ($) 
         | 
        
           Jun. 30, 2013
 
          HML
 
          USD ($) 
         | 
        
           Jun. 30, 2013
 
          PSI
 
          USD ($) 
         | 
        
           Apr. 30, 2012
 
          PSI
 
          USD ($) 
         | 
        
           Sep. 30, 2012
 
          PSI
 
          Previously reported
 
          USD ($) 
         | 
        
           Jun. 30, 2013
 
          PSI
 
          Adjusted
 
          USD ($) 
         | 
      |
| Acquisitions | ||||||||||||
| Share capital acquired (as a percent) | 100.00% | 100.00% | 100.00% | |||||||||
| Acquisition-related expenses | $ 1,174 | $ 1,877 | $ 1,500 | $ 2,110 | $ 900 | $ 900 | ||||||
| Purchase price allocation | ||||||||||||
| Cash consideration, net of cash acquired | 71,435 | 46,900 | 63,400 | |||||||||
| Stock consideration | 7,559 | 5,000 | ||||||||||
| Stock consideration (in shares) | 202,972 | 202,972 | ||||||||||
| Purchase consideration, net of cash acquired | 78,994 | 51,900 | ||||||||||
| Accounts receivable and unbilled receivables | 12,002 | 23,017 | 23,017 | |||||||||
| Other current assets | 807 | 9,527 | 9,527 | |||||||||
| Deferred income taxes | 2,129 | 1,931 | 198 | |||||||||
| Property and equipment | 2,740 | 6,411 | 6,411 | |||||||||
| Other assets | 1,332 | 1,332 | ||||||||||
| Intangible assets | 22,183 | 22,183 | ||||||||||
| Total identifiable assets acquired | 15,549 | 64,599 | 64,401 | 198 | ||||||||
| Accounts payable and other liabilities | 10,495 | 20,666 | 20,666 | |||||||||
| Deferred revenue | 1,295 | 19,775 | 19,696 | 79 | ||||||||
| Total liabilities assumed | 11,790 | 40,441 | 40,362 | 79 | ||||||||
| Net identifiable assets acquired | 3,759 | |||||||||||
| Net identifiable assets acquired | 24,158 | 24,039 | 119 | |||||||||
| Goodwill and intangible assets | 75,235 | |||||||||||
| Goodwill | 39,290 | 39,161 | 129 | |||||||||
| Net assets acquired | $ 78,994 | $ 63,448 | $ 63,200 | $ 248 | ||||||||
| Number of business segments | 2 | |||||||||||
| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to accounts payable and other liabilities of the acquired entity. No definition available. 
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| X | ||||||||||
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- Definition 
          Amount of acquisition cost of a business combination allocated to goodwill and intangible assets. No definition available. 
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| X | ||||||||||
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- Definition 
          Amount of acquisition cost of a business combination allocated to other current assets not separately disclosed. No definition available. 
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| X | ||||||||||
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- Definition 
          The net amount recognized as of the acquisition date for the aggregate assets, excluding goodwill, in excess of or less than the aggregate liabilities assumed. No definition available. 
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| X | ||||||||||
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- Definition 
          The net amount recognized as of the acquisition date for the aggregate assets, excluding goodwill and intangible assets, in excess of or less than the aggregate liabilities assumed. No definition available. 
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| X | ||||||||||
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- Details 
          
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| X | ||||||||||
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- Definition 
          Amount of cash paid to acquire the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The acquisition-date fair value of the equity interests of the acquirer, including the number of instruments or interests issued or issuable in consideration for the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Number of shares of equity interests issued or issuable to acquire entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
          
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| X | ||||||||||
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- Definition 
          Percentage of voting equity interests acquired in the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to an identifiable intangible asset that will be amortized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to assets acquired. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to receivables. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to deferred revenue of the acquired entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Gross amount of acquisition cost of a business combination allocated to noncurrent deferred tax assets. No definition available. 
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| X | ||||||||||
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- Definition 
          Amount of goodwill arising from a business combination, which is the excess of the cost of the acquired entity over the amounts assigned to assets acquired and liabilities assumed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to liabilities assumed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Amount of acquisition cost of a business combination allocated to other noncurrent assets not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of acquisition cost of a business combination allocated to property, plant and equipment to be used in ongoing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Net amount recognized for aggregate assets, including goodwill, in excess of or less than the aggregate liabilities assumed (also referred to as net assets acquired). This amount may also be viewed as incremental amount of equity that the consolidated entity (including the portion attributable to a noncontrolling interest) will recognize as a result of the business combination. No definition available. 
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| X | ||||||||||
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- Definition 
          Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. No definition available. 
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