Operating Segments - Reconciliation of Operating Profit (Loss) from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	$ 109,479	$ 81,064	$ 274,282	$ 200,414
Cost of revenue	70,166	50,147	191,633	138,955
Gross profit	39,313	30,917	82,649	61,459
Operating expenses	29,066	25,254	96,252	78,820
Net income (loss)	10,558	5,700	(13,203)	(17,191)	$ (22,526)
Real Estate
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	103,864	79,198	262,894	195,203
Cost of revenue	64,258	47,966	178,850	132,990
Gross profit	39,606	31,232	84,044	62,213
Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	5,615	1,866	11,388	5,211
Cost of revenue	5,908	2,181	12,783	5,965
Gross profit	$ (293)	$ (315)	$ (1,395)	$ (754)