Acquisition of Citizen Engagement Centers Business - Schedule of the Valuation of the Intangible Assets Acquired (Details) - General Dynamics Information Technology's Citizen Engagement Centers $ in Thousands	9 Months Ended
	Jun. 30, 2019 USD ($)
Finite-Lived Intangible Assets [Line Items]
Fair value	$ 122,300
Customer relationships - all contracts except U.S. Census
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Fair value	$ 85,300
Customer relationships - U.S. Census
Finite-Lived Intangible Assets [Line Items]
Useful life	2 years
Fair value	$ 37,000