Reportable Segments - Schedule of Gross Profit by Reportable Segment (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Segment Reporting Information [Line Items]                      
Total gross profit $ 13,177 $ 47,978 $ 13,729 $ 8,280 $ 23,164 $ 46,185 $ 17,490 $ 9,274 $ 83,164 $ 96,113 $ 61,419
Operating Segments | Government gross profit                      
Segment Reporting Information [Line Items]                      
Total gross profit                 161,809 146,149 64,636
Operating Segments | Commercial gross profit                      
Segment Reporting Information [Line Items]                      
Total gross profit                 55,382 53,541 42,904
Non-allocated costs                      
Segment Reporting Information [Line Items]                      
Non-allocated costs                 $ (134,027) [1] $ (103,577) [1] $ (46,121) [1]
[1] Non-allocated costs include costs that are shared by both of the reporting segments but are not allocated to the operating segments for the use of the CODM and expenses that are not directly attributable to the operating segments.