Annual report pursuant to Section 13 and 15(d)

Business combinations and disposals - Schedule of Assets and Liabilities Recorded in the Company's Financial Statements (Details)

v3.8.0.1
Business combinations and disposals - Schedule of Assets and Liabilities Recorded in the Company's Financial Statements (Details) - USD ($)
$ in Thousands
 12 Months Ended
Feb. 29, 2016
Sep. 30, 2017
Sep. 30, 2016
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]      
Goodwill     $ 21,453
Ascend Management Innovations LLC      
Business Combination, Consideration Transferred      
Purchase consideration, net of cash acquired $ 44,100 $ 44,069  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]      
Billed and unbilled receivables   4,069  
Other assets   407  
Property and equipment and other assets   707  
Deferred income taxes   557  
Intangible assets 22,300 22,300  
Total identifiable assets acquired   28,040  
Accounts payable and other liabilities   1,414  
Deferred revenue   554  
Total liabilities assumed   1,968  
Net identifiable assets acquired   26,072  
Goodwill $ 18,000 17,997  
Net assets acquired   44,069  
Scenario, Previously Reported [Member] | Ascend Management Innovations LLC      
Business Combination, Consideration Transferred      
Purchase consideration, net of cash acquired     44,069
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]      
Billed and unbilled receivables     4,069
Other assets     407
Property and equipment and other assets     707
Deferred income taxes     0
Intangible assets     22,300
Total identifiable assets acquired     27,483
Accounts payable and other liabilities     1,414
Deferred revenue     554
Total liabilities assumed     1,968
Net identifiable assets acquired     25,515
Goodwill     18,554
Net assets acquired     $ 44,069
Scenario, Adjustment [Member] | Ascend Management Innovations LLC      
Business Combination, Consideration Transferred      
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred   0  
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]      
Adjustments, billed and unbilled receivables   0  
Adjustments, other noncurrent assets   0  
Adjustments, property and equipment and other assets   0  
Adjustments, deferred income taxes   557  
Adjustments, intangibles assets   0  
Adjustments, total identifiable assets acquired   557  
Adjustments, accounts payable and other liabilities   0  
Adjustments, deferred revenue   0  
Adjustments, total liabilities assumed   0  
Adjustments, net identifiable assets acquired   557  
Adjustments, goodwill   (557)  
Adjustments, recognized identifiable assets acquired, goodwill, and liabilities assumed, net   $ 0