Revenue - Cost and Estimated Earnings on Uncompleted Contract (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated earnings to date	$ 6,477	$ 6,000
Estimated costs to date	(5,289)	(4,525)
Subtotal	1,188	1,475
Net billings to date	(108)	2,718
Unbilled project costs	1,343	4,998
Cost and estimated earnings in excess of billings	(263)	(805)
Total	$ 1,080	4,193
As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated earnings to date		5,867
Estimated costs to date		(4,525)
Subtotal		1,342
Net billings to date		2,718
Unbilled project costs		4,865
Cost and estimated earnings in excess of billings		(805)
Total		4,060
Restatement Adjustment | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated earnings to date		(133)
Estimated costs to date		0
Subtotal		(133)
Net billings to date		0
Unbilled project costs		(133)
Cost and estimated earnings in excess of billings		0
Total		$ (133)