Construction Contracts - Summary of Net Position (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Contractors [Abstract]
Costs incurred on uncompleted construction contracts	$ 562,879	$ 520,368
Estimated earnings	19,222	18,070
Billings	(582,525)	(541,784)
Net position	(424)	(3,346)
Construction contract costs and estimated earnings in excess of billings	1,287	245
Billings in excess of construction contract costs and estimated earnings	$ (1,711)	$ (3,591)

Amount of receivable reflecting the cost incurred on uncompleted contracts in excess of related billings.

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