Construction Contracts - Summary of Net Position (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Contractors [Abstract]
Costs incurred on uncompleted construction contracts	$ 360,247	$ 461,725
Estimated earnings	14,427	13,205
Billings	(376,978)	(480,880)
Net position	(2,304)	(5,950)
Construction contract costs and estimated earnings in excess of billings	370	138	$ 215	$ 249
Billings in excess of construction contract costs and estimated earnings	$ (2,674)	$ (6,088)	$ (7,085)	$ (5,306)