Revenue Recognition - Additional Information (Details) $ in Thousands	Dec. 31, 2018 USD ($) contract	Dec. 31, 2017 USD ($) contract	Dec. 31, 2016 USD ($)
Revenue from Contract with Customer [Abstract]
Unbilled receivables, current	$ 5,540	$ 7,894	$ 6,755
Billings in excess of costs and estimated earnings on uncompleted contracts	$ (1,234)	$ (2,403)	$ 1,730
Number of contracts | contract	5
Number of contracts identified as loss contracts | contract		4
Provision for losses on contracts	$ 123	$ 117
Remaining performance obligations	12,384
Remaining performance obligations expected to be recognized in 12 months	$ 10,622