Construction Contracts - Summary of Net Position (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Contractors [Abstract]
Costs incurred on uncompleted construction contracts	$ 852,966	$ 695,564
Estimated earnings	30,354	24,553
Billings	(890,190)	(725,174)
Net position	(6,870)	(5,057)
Construction contract costs and estimated earnings in excess of billings, net	215	249	$ 624	$ 1,358
Billings in excess of construction contract costs and estimated earnings	$ (7,085)	$ (5,306)	$ (3,333)	$ (3,037)