Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total Revenue	$ 61,555	$ 51,459	$ 180,913	$ 158,495
Prime Contractor
Disaggregation of Revenue [Line Items]
Total Revenue	53,407	47,649	159,059	147,464
Subcontractor
Disaggregation of Revenue [Line Items]
Total Revenue	8,148	3,810	21,854	11,031
Time and Materials
Disaggregation of Revenue [Line Items]
Total Revenue	46,790	36,315	137,492	110,918
Cost Reimbursable
Disaggregation of Revenue [Line Items]
Total Revenue	12,070	13,841	35,796	43,887
Firm Fixed Price
Disaggregation of Revenue [Line Items]
Total Revenue	2,695	1,303	7,625	3,690
Department of Veterans Affairs
Disaggregation of Revenue [Line Items]
Total Revenue	27,496	24,783	83,010	74,402
Department of Health and Human Services
Disaggregation of Revenue [Line Items]
Total Revenue	23,245	23,312	66,748	73,263
Department of Defense
Disaggregation of Revenue [Line Items]
Total Revenue	7,601	270	22,103	943
Other
Disaggregation of Revenue [Line Items]
Total Revenue	$ 3,213	$ 3,094	$ 9,052	$ 9,887