Segments - Additional information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information
Segment revenues	$ 50,475	$ 38,552	$ 33,200	$ 36,803	$ 41,309	$ 53,822	$ 47,066	$ 29,071	$ 159,030	$ 171,268	$ 103,321
General contracting and real estate services expenses									153,375	165,344	98,754
Non-cash stock compensation									1,082	931	917
General and Administrative Expenses
Segment Reporting Information
Non-cash stock compensation									700	700	700
General contracting and real estate services
Segment Reporting Information
Non-cash stock compensation									200	200	200
General contracting and real estate services | Intersegment Eliminations
Segment Reporting Information
Segment revenues									43,300	43,100	85,400
General contracting and real estate services expenses									$ 42,700	$ 42,800	$ 84,600