Construction Contracts - Summary of Net Position (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Contractors [Abstract]
Costs incurred on uncompleted construction contracts	$ 939,312	$ 905,037
Estimated earnings	33,399	32,130
Billings	(975,719)	(943,117)
Net position	(3,008)	(5,950)
Construction contract costs and estimated earnings in excess of billings	54	138	$ 458	$ 249
Billings in excess of construction contract costs and estimated earnings	$ (3,062)	$ (6,088)	$ (6,311)	$ (5,306)