Organization and Basis of Presentation and Combination - Schedule of revenue by major customer (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Disaggregation of Revenue [Line Items]
Revenues	$ 118,020	$ 116,339	$ 234,292	$ 233,123
U.S. federal government
Disaggregation of Revenue [Line Items]
Revenues	$ 23,168	$ 23,326	$ 46,377	$ 47,345
U.S. federal government contracts concentration risk | Office segment revenue
Disaggregation of Revenue [Line Items]
Percentage of revenue	26.74%	26.03%	26.80%	26.26%
U.S. federal government contracts concentration risk | Total revenue
Disaggregation of Revenue [Line Items]
Percentage of revenue	19.63%	20.05%	19.79%	20.31%