Construction Contracts - Summary of Net Position (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Contractors [Abstract]
Costs incurred on uncompleted construction contracts	$ 957,444	$ 905,037
Estimated earnings	33,645	32,130
Billings	(995,141)	(943,117)
Net position	(4,052)	(5,950)
Construction contract costs and estimated earnings in excess of billings	85	138	$ 333	$ 249
Billings in excess of construction contract costs and estimated earnings	$ (4,137)	$ (6,088)	$ (9,320)	$ (5,306)