Operating Segments - Schedule of Real Estate Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total real estate revenue	$ 104,935	$ 77,714	$ 164,802	$ 119,349
Real Estate
Segment Reporting Information [Line Items]
Total real estate revenue	100,658	75,649	159,030	116,006
Brokerage Revenue | Real Estate
Segment Reporting Information [Line Items]
Total real estate revenue	95,069	71,401	149,540	109,388
Partner Revenue | Real Estate
Segment Reporting Information [Line Items]
Total real estate revenue	$ 5,589	$ 4,248	$ 9,490	$ 6,618