Notes and Interest Receivable - Summary of the interest income from related parties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest Income, Related Party	$ 4,721	$ 5,888
Arlo
Interest Income, Related Party		1,020
Avondale Hills Member
Interest Income, Related Party	117
Domain at The One Forty [Member]
Interest Income, Related Party	239	322
Motif [Member]
Interest Income, Related Party	2,374	2,400
Novel Perimeter
Interest Income, Related Party		770
Reunion Apartments [Member]
Interest Income, Related Party	290
The Hartley at Blue Hill, formerly The Park at Chapel Hill [Member]
Interest Income, Related Party	1,023	935
Vickers Historic Roswell [Member]
Interest Income, Related Party	440	429
Zoey [Member]
Interest Income, Related Party	$ 238	$ 12