Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) ReportingUnit	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounting Policies [Abstract]
Restricted cash | $	$ 4,111	$ 2,048
Total number of the Company's reporting units | ReportingUnit	5
Number of reporting units which have goodwill associated with them | ReportingUnit	3
Customer [Line Items]
Contracts Revenue | $	$ 42,500	$ 200	$ 1,900
SBB
Customer [Line Items]
Change in Margin	2.00%
SBB | Contract 1
Customer [Line Items]
Percentage Complete	45.00%
SBB | Contract 2
Customer [Line Items]
Percentage Complete	0.00%