Adoption of ASU 606 - Effects of the Adoption of ASU Topic 606 (Details) - USD ($)
$ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |
|
|
| Receivables (unbilled) |
$ 121,601
|
|
| Costs incurred in excess of billings |
12,751
|
$ 11,002
|
| Billings in excess of costs |
3,766
|
1,421
|
| Impact to contract liabilities |
0
|
|
| Retained earnings |
117,415
|
$ 0
|
| Accounting Standards Update 2014-09 | Pro forma |
|
|
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |
|
|
| Receivables (unbilled) |
132,058
|
|
| Costs incurred in excess of billings |
0
|
|
| Billings in excess of costs |
0
|
|
| Impact to contract liabilities |
1,621
|
|
| Retained earnings |
117,317
|
|
| Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Pro forma |
|
|
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |
|
|
| Receivables (unbilled) |
10,457
|
|
| Costs incurred in excess of billings |
(12,751)
|
|
| Billings in excess of costs |
(3,766)
|
|
| Impact to contract liabilities |
1,621
|
|
| Retained earnings |
$ (98)
|
|