Notes Receivable - Schedule of Notes Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 130,626	$ 143,087
Notes Receivable
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	130,626	143,087
Notes Receivable | ABC Land and Development, Inc.
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 4,408	4,408
Interest Rate	9.50%
Notes Receivable | ABC Paradise, LLC
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 1,210	1,210
Interest Rate	9.50%
Notes Receivable | Autumn Breeze
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 1,867	1,302
Interest Rate	5.00%
Notes Receivable | Bellwether Ridge
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 3,858	3,765
Interest Rate	5.00%
Notes Receivable | Centura Towers
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 0	19,845
Interest Rate	2.28%
Notes Receivable | Forest Pines
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 2,869	2,868
Interest Rate	5.00%
Notes Receivable | JEM Holdings, Inc.
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 0	300
Interest Rate	6.00%
Notes Receivable | Lake Wales
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 3,000	3,000
Interest Rate	9.50%
Notes Receivable | Legacy Pleasant Grove
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 496	496
Interest Rate	12.00%
Notes Receivable | McKinney Ranch
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 4,554	4,554
Interest Rate	6.00%
Notes Receivable | One Realco Land Holding, Inc.
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 1,728	1,728
Interest Rate	9.50%
Notes Receivable | Oulad Chikh Family Trust
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 0	174
Interest Rate	8.00%
Notes Receivable | Parc at Ingleside
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 2,523	1,531
Interest Rate	5.00%
Notes Receivable | Parc at Windmill Farms
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 7,803	7,602
Interest Rate	5.00%
Ownership interest if note converted	100.00%
Notes Receivable | Phillips Foundation For Better Living Inc ., Maturing 2022
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 0	314
Interest Rate	12.00%
Notes Receivable | Phillips Foundation For Better Living Inc., Maturing 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 61	0
Interest Rate	12.00%
Notes Receivable | Plum Tree
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 857	413
Interest Rate	5.00%
Notes Receivable | Riverview on the Park Land, LLC
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 1,045	1,045
Interest Rate	9.50%
Notes Receivable | RNC Portfolio, Inc.
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 8,853	8,802
Interest Rate	5.00%
Notes Receivable | Spartan Land
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 5,907	5,907
Interest Rate	12.00%
Notes Receivable | Spyglass of Ennis
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 5,360	5,288
Interest Rate	5.00%
Notes Receivable | Steeple Crest
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 6,498	6,665
Interest Rate	5.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing July 31, 2021
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 2,880	3,793
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc ., Maturing August 30, 2021
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 212	212
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing October 31, 2021
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 6,831	6,831
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing December 31, 2021
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 10,896	10,926
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing March 31, 2022
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 10,096	10,096
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing March 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 6,990	0
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing May 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 3,615	0
Interest Rate	12.00%
Notes Receivable | Unified Housing Foundation Inc., Maturing December 31, 2032
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Notes receivable	$ 26,209	$ 30,012
Interest Rate	12.00%