Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total	$ 70,066	$ 47,440	$ 178,383	$ 135,029
Firm-fixed-price
Disaggregation of Revenue [Line Items]
Total	61,434	39,483	155,832	113,080
Time-and-materials
Disaggregation of Revenue [Line Items]
Total	3,154	3,605	9,243	11,066
Cost plus fixed fee
Disaggregation of Revenue [Line Items]
Total	5,478	4,352	13,308	10,883
Federal Government
Disaggregation of Revenue [Line Items]
Total	67,697	45,788	171,091	128,756
State & Local, and Commercial
Disaggregation of Revenue [Line Items]
Total	$ 2,369	$ 1,652	$ 7,292	$ 6,273