Construction Contracts - Summary of Costs in Excess of Billings and Billings in Excess of Costs (Details) $ in Thousands	6 Months Ended
Jun. 30, 2018 USD ($)
Change In Contract With Customer, Asset [Roll Forward]
Balance as of January 1, 2018	$ 245
Transferred to receivables	(245)
Construction contract costs and estimated earnings not billed during the period	1,287
Changes due to cumulative catch-up adjustment arising from changes in the estimate of the stage of completion	0
Balance as of June 30, 2018	1,287
Change In Contract With Customer, Liability [Roll Forward]
Balance as of January 1, 2018	3,591
Revenue recognized that was included in the balance at the beginning of the period	(3,591)
Increases due to new billings, excluding amounts recognized as revenue during the period	1,898
Changes due to cumulative catch-up adjustment arising from changes in the estimate of the stage of completion	(187)
Balance as of June 30, 2018	$ 1,711

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Change In Contract With Customer, Liability [Roll Forward]

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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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