Revenue from Contracts with Clients - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 94,449	$ 98,257	$ 187,757	$ 196,940
Percent of Total Revenue	100.00%	100.00%	100.00%	100.00%
United States
Disaggregation of Revenue [Line Items]
Revenue	$ 49,785	$ 51,336	$ 95,805	$ 99,438
Percent of Total Revenue	52.70%	52.30%	51.00%	50.60%
Latin America
Disaggregation of Revenue [Line Items]
Revenue	$ 659	$ 1,911	$ 1,830	$ 4,345
Percent of Total Revenue	0.70%	1.90%	1.00%	2.20%
Europe
Disaggregation of Revenue [Line Items]
Revenue	$ 14,432	$ 10,622	$ 25,969	$ 21,956
Percent of Total Revenue	15.30%	10.80%	13.80%	11.10%
Middle East
Disaggregation of Revenue [Line Items]
Revenue	$ 21,529	$ 25,972	$ 46,101	$ 54,283
Percent of Total Revenue	22.80%	26.40%	24.50%	27.60%
Africa
Disaggregation of Revenue [Line Items]
Revenue	$ 7,258	$ 6,930	$ 14,555	$ 13,879
Percent of Total Revenue	7.70%	7.10%	7.80%	7.00%
Asia/Pacific
Disaggregation of Revenue [Line Items]
Revenue	$ 786	$ 1,486	$ 3,497	$ 3,039
Percent of Total Revenue	0.80%	1.50%	1.90%	1.50%
Fixed Price
Disaggregation of Revenue [Line Items]
Revenue	$ 20,259	$ 20,847	$ 37,971	$ 44,585
Fixed Price | United States
Disaggregation of Revenue [Line Items]
Revenue	4,200	3,680	9,223	7,113
Fixed Price | Latin America
Disaggregation of Revenue [Line Items]
Revenue	296	1,973	1,467	3,989
Fixed Price | Europe
Disaggregation of Revenue [Line Items]
Revenue	11,750	5,302	18,179	11,353
Fixed Price | Middle East
Disaggregation of Revenue [Line Items]
Revenue	3,943	8,864	8,826	20,230
Fixed Price | Africa
Disaggregation of Revenue [Line Items]
Revenue	70	600	276	1,171
Fixed Price | Asia/Pacific
Disaggregation of Revenue [Line Items]
Revenue	0	428	0	729
T&M
Disaggregation of Revenue [Line Items]
Revenue	74,190	77,410	149,786	152,355
T&M | United States
Disaggregation of Revenue [Line Items]
Revenue	45,585	47,656	86,582	92,325
T&M | Latin America
Disaggregation of Revenue [Line Items]
Revenue	363	(62)	363	356
T&M | Europe
Disaggregation of Revenue [Line Items]
Revenue	2,682	5,320	7,790	10,603
T&M | Middle East
Disaggregation of Revenue [Line Items]
Revenue	17,586	17,108	37,275	34,053
T&M | Africa
Disaggregation of Revenue [Line Items]
Revenue	7,188	6,330	14,279	12,708
T&M | Asia/Pacific
Disaggregation of Revenue [Line Items]
Revenue	$ 786	$ 1,058	$ 3,497	$ 2,310