Construction Contracts - Summary of Costs in Excess of Billings and Billings in Excess of Costs (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Construction contract costs and estimated earnings in excess of billings
Beginning balance	$ 1,358	$ 245
Transferred to receivables	(1,358)	(245)
Construction contract costs and estimated earnings not billed during the period	17	315
Changes due to cumulative catch-up adjustment arising from changes in the estimate of the stage of completion	300	0
Ending balance	317	315
Billings in excess of construction contract costs and estimated earnings
Beginning balance	3,037	3,591
Revenue recognized that was included in the balance at the beginning of the period	(3,037)	(3,591)
Increases due to new billings, excluding amounts recognized as revenue during the period	3,859	2,313
Changes due to cumulative catch-up adjustment arising from changes in the estimate of the stage of completion	(237)	(78)
Ending balance	$ 3,622	$ 2,235

Change In Contract With Customer, Asset [Roll Forward]

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Change In Contract With Customer, Liability [Roll Forward]

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Contract With Customer, Asset, Costs And Earnings Not Billed

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Contract With Customer, Liability, Increase From Billings

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in measure of progress which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time from transfer to receivable due to right to consideration becoming unconditional.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in measure of progress which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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