Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Revenue	$ 51,459	$ 38,700	$ 158,495	$ 106,208
Prime contractor
Disaggregation of Revenue [Line Items]
Total Revenue	47,649	36,882	147,464	103,947
Subcontractor
Disaggregation of Revenue [Line Items]
Total Revenue	3,810	1,818	11,031	2,261
Time and materials
Disaggregation of Revenue [Line Items]
Total Revenue	36,315	33,426	110,918	98,841
Cost reimbursable
Disaggregation of Revenue [Line Items]
Total Revenue	13,841	4,545	43,887	5,791
Firm fixed price
Disaggregation of Revenue [Line Items]
Total Revenue	1,303	729	3,690	1,576
Department of Veterans Affairs
Disaggregation of Revenue [Line Items]
Total Revenue	24,783	23,056	74,402	68,563
Department of Health and Human Services
Disaggregation of Revenue [Line Items]
Total Revenue	23,312	14,297	73,263	34,987
Other
Disaggregation of Revenue [Line Items]
Total Revenue	$ 3,364	$ 1,347	$ 10,830	$ 2,658