Annual report pursuant to Section 13 and 15(d)

Contract Revenue and Percentage-of-Completion Method - Revenues by Geographic Location (Details)

v3.6.0.2
Contract Revenue and Percentage-of-Completion Method - Revenues by Geographic Location (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Geographic Reporting Disclosure [Line Items]                      
Revenue $ 55,461 $ 65,384 $ 81,502 $ 83,979 $ 55,018 $ 67,531 $ 84,338 $ 99,233 $ 286,326 $ 306,120 $ 506,639
United States                      
Geographic Reporting Disclosure [Line Items]                      
Revenue                 245,039 287,892 456,839
International                      
Geographic Reporting Disclosure [Line Items]                      
Revenue                 $ 41,287 $ 18,228 $ 49,800