Revenue and Contract Costs (Tables)

6 Months Ended

Jun. 30, 2017

Contractors [Abstract]

Pass-through Costs as a Percentage of Revenue

Our pass-through costs as a percentage of revenue for each period presented were as follows:

	Three Months Ended June 30,		Six Months Ended June 30,
	2017	2016	2017	2016
Pass-through costs as a percentage of revenues	53.1%	35.1%	41.9%	37.6%