Segments - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information
General contracting and real estate services revenues	$ 58,617	$ 27,638	$ 163,283	$ 66,118
General contracting and real estate services | General contracting and real estate services | Intercompany Eliminations
Segment Reporting Information
General contracting and real estate services revenues	3,200	22,400	24,700	82,600
General contracting and real estate services expenses	$ 3,200	$ 22,200	$ 24,500	$ 81,800