Annual report pursuant to Section 13 and 15(d)

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

v3.19.3
Business combinations and disposal - Schedule of Assets and Liabilities Recorded in the Company's Financial Statements (Details) - USD ($)
$ in Thousands
9 Months Ended 12 Months Ended
Nov. 16, 2018
Jun. 30, 2019
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]          
Goodwill     $ 584,469 $ 399,882 $ 402,976
General Dynamics Information Technology's Citizen Engagement Centers          
Business Combination, Consideration Transferred          
Cash consideration $ 430,700 $ 430,699 430,723    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]          
Billed and unbilled receivables   142,165 142,077    
Property and equipment   8,974 13,961    
Other assets   4,508 4,530    
Intangible assets   122,300 122,300    
Total identifiable assets acquired   277,947 282,868    
Accounts payable and other liabilities   31,862 36,785    
Net identifiable assets acquired   246,085 246,083    
Goodwill   184,614 184,640    
Net assets acquired   $ 430,699 430,723    
General Dynamics Information Technology's Citizen Engagement Centers | Scenario, Adjustment          
Business Combination, Consideration Transferred          
Cash consideration     24    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]          
Billed and unbilled receivables     (88)    
Property and equipment     4,987    
Other assets     22    
Intangible assets     0    
Total identifiable assets acquired     4,921    
Accounts payable and other liabilities     4,923    
Net identifiable assets acquired     (2)    
Goodwill     26    
Net assets acquired     $ 24