Annual report pursuant to Section 13 and 15(d)

Business combinations and disposal - Schedule of Goodwill (Details)

v3.19.3
Business combinations and disposal - Schedule of Goodwill (Details) - USD ($)
 12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Changes in goodwill    
Balance at the beginning of the period $ 399,882,000 $ 402,976,000
Foreign currency translation (1,772,000) (3,094,000)
Other 372,000  
Balance at the end of the period 584,469,000 399,882,000
Goodwill impairment loss 0  
General Dynamics Information Technology's Citizen Engagement Centers    
Changes in goodwill    
Goodwill acquired through acquisition 184,640,000  
Balance at the end of the period 184,640,000  
GT Hiring Solutions    
Changes in goodwill    
Goodwill acquired through acquisition 1,347,000  
U.S. Health and Human Services    
Changes in goodwill    
Balance at the beginning of the period 139,588,000 139,588,000
Foreign currency translation 0 0
Other 0  
Balance at the end of the period 164,472,000 139,588,000
U.S. Health and Human Services | General Dynamics Information Technology's Citizen Engagement Centers    
Changes in goodwill    
Goodwill acquired through acquisition 24,884,000  
U.S. Health and Human Services | GT Hiring Solutions    
Changes in goodwill    
Goodwill acquired through acquisition 0  
U.S. Federal Services    
Changes in goodwill    
Balance at the beginning of the period 228,148,000 228,148,000
Foreign currency translation 0 0
Other 0  
Balance at the end of the period 382,618,000 228,148,000
U.S. Federal Services | General Dynamics Information Technology's Citizen Engagement Centers    
Changes in goodwill    
Goodwill acquired through acquisition 154,470,000  
U.S. Federal Services | GT Hiring Solutions    
Changes in goodwill    
Goodwill acquired through acquisition 0  
Outside the U.S.    
Changes in goodwill    
Balance at the beginning of the period 32,146,000 35,240,000
Foreign currency translation (1,772,000) (3,094,000)
Other 372,000  
Balance at the end of the period 37,379,000 $ 32,146,000
Outside the U.S. | General Dynamics Information Technology's Citizen Engagement Centers    
Changes in goodwill    
Goodwill acquired through acquisition 5,286,000  
Outside the U.S. | GT Hiring Solutions    
Changes in goodwill    
Goodwill acquired through acquisition $ 1,347,000