Mortgages and Other Notes Payable - Schedule of Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Aug. 25, 2021	Jun. 04, 2021	Mar. 04, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 183,392				$ 242,711
600 Las Colinas
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 0				35,589
Interest Rate	5.30%
770 South Post Oak
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 11,635				11,871
Interest Rate	4.40%
Athens
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 1,155				1,155
Interest Rate	4.00%
Chelsea
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 8,037				8,194
Interest Rate	3.40%
EQK Portage - Land
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 3,350				3,350
Interest Rate	10.00%
HSW Partners
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 0				17,790
Interest Rate	9.50%
Forest Grove
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 7,263				7,333
Interest Rate	3.75%
Forest Grove | Prime Rate
Debt Instrument [Line Items]
Variable interest rate	0.50%
Landing Bayou
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 14,407				14,643
Interest Rate	3.50%
Legacy at Pleasant Grove
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 13,352				13,653
Interest Rate	3.60%
McKinney 36 Land
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 0				820
Interest Rate	8.00%
New Concept Energy
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 3,542				3,542
Interest Rate	6.00%
Overlook at Allensville Phase II
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 0				15,621
Interest Rate	3.80%
Parc at Denham Springs Phase II
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 15,962				16,128
Interest Rate	4.10%
RCM HC Enterprises
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 5,086				0
Interest Rate	9.50%
RCM HC Enterprises | Mortgages
Debt Instrument [Line Items]
Mortgages and other notes payable			$ 1,986
Stanford Center
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 38,979				39,093
Interest Rate	6.00%
Sugar Mill Phase III
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 9,216				9,298
Interest Rate	4.50%
Toulon
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 13,697				13,975
Interest Rate	3.20%
Villas at Bon Secour
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 19,492				10,280
Interest Rate	3.08%
Villas at Bon Secour | Mortgages
Debt Instrument [Line Items]
Mortgages and other notes payable		$ 20,015
Interest Rate		3.08%
Vista Ridge
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 9,830				9,979
Interest Rate	4.00%
Windmill Farms
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 8,389				$ 10,397
Interest Rate	5.00%			5.00%