Mortgages and Notes Payable (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020	Dec. 31, 2019
Carrying value		$ 242,300	$ 245,773
Mortgages and Notes Payable [Member]
Carrying value		242,300	245,772
Mortgages and Notes Payable [Member] | 600 Las Colinas Building [Member]
Carrying value		$ 35,773	36,302
Effective Interest Rate		5.30%
Maturity Date		Nov. 01, 2023
Mortgages and Notes Payable [Member] | 770 South Post Oak Building [Member]
Carrying value		$ 11,924	12,077
Effective Interest Rate		4.40%
Maturity Date		Jun. 01, 2025
Mortgages and Notes Payable [Member] | Bridgeview Plaza Shopping Center [Member]
Carrying value	[1]		3,824
Effective Interest Rate	[1]	7.75%
Maturity Date	[1]	Nov. 01, 2020
Mortgages and Notes Payable [Member] | Chelsea Apartments [Member]
Carrying value		$ 8,627	8,749
Effective Interest Rate		3.40%
Maturity Date		Dec. 01, 2050
Mortgages and Notes Payable [Member] | EQK Portage-Kent Ohio Land [Member]
Carrying value	[2]	$ 3,350
Effective Interest Rate	[2]	10.00%
Maturity Date	[2]	Nov. 13, 2024
Mortgages and Notes Payable [Member] | Estate Of Robert Shaw [Member]
Carrying value	[3]	$ 13,065	13,032
Effective Interest Rate	[3]	9.50%
Maturity Date	[3]	Jul. 05, 2020
Mortgages and Notes Payable [Member] | Farnham Apartments [Member]
Carrying value	[4]		9,144
Effective Interest Rate	[4]	3.39%
Maturity Date	[4]	Dec. 01, 2050
Mortgages and Notes Payable [Member] | Forest Pines Phase II [Member]
Carrying value	[5]		1,390
Effective Interest Rate	[5]	3.75%
Maturity Date	[5]	May 05, 2024
Mortgages and Notes Payable [Member] | Forest Pines Phase II Apartments [Member]
Carrying value	[5]	$ 7,057
Effective Interest Rate	[5]	3.75%
Maturity Date	[5]	May 05, 2024
Mortgages and Notes Payable [Member] | Landing Apartments [Member]
Carrying value		$ 15,286	15,467
Effective Interest Rate		3.50%
Maturity Date		Sep. 01, 2053
Mortgages and Notes Payable [Member] | Ld Athens Lindsay Ln Land [Member]
Carrying value		$ 1,155	1,155
Effective Interest Rate		5.90%
Maturity Date		Feb. 28, 2021
Mortgages and Notes Payable [Member] | Legacy At Pleasant Grove Apartments [Member]
Carrying value		$ 13,727	13,944
Effective Interest Rate		3.60%
Maturity Date		Apr. 01, 2048
Mortgages and Notes Payable [Member] | Mckinney 36 Land [Member]
Carrying value		$ 856	944
Effective Interest Rate		8.00%
Maturity Date		Jun. 30, 2022
Mortgages and Notes Payable [Member] | Overlook At Allensville Phase II Apartments [Member]
Carrying value		$ 15,666	15,798
Effective Interest Rate		3.80%
Maturity Date		May 01, 2059
Mortgages and Notes Payable [Member] | Parc At Denham Spring Phase II Apartments [Member]
Carrying value		$ 16,168	14,785
Effective Interest Rate		4.10%
Maturity Date		Feb. 01, 2060
Mortgages and Notes Payable [Member] | Stanford Center Building [Member]
Carrying value		$ 39,191	39,255
Effective Interest Rate		6.00%
Maturity Date		Dec. 26, 2021
Mortgages and Notes Payable [Member] | Sugar Mill Phase III Apartments [Member]
Carrying value			5,908
Effective Interest Rate		4.50%
Maturity Date		Feb. 01, 2060
Mortgages and Notes Payable [Member] | Sugar Mill Phase III Apartments [Member]
Carrying value		$ 8,906
Effective Interest Rate		4.50%
Maturity Date		Feb. 01, 2060
Mortgages and Notes Payable [Member] | Toulon Apartments [Member]
Carrying value		$ 18,283	18,465
Effective Interest Rate		3.20%
Maturity Date		Dec. 01, 2051
Mortgages and Notes Payable [Member] | Villager Apartments [Member]
Carrying value	[6]		556
Effective Interest Rate	[6]	2.50%
Maturity Date	[6]	Mar. 01, 2043
Mortgages and Notes Payable [Member] | Villas At Bon Secour Apartments [Member]
Carrying value		$ 10,860	11,026
Effective Interest Rate		4.00%
Maturity Date		Jan. 01, 2022
Mortgages and Notes Payable [Member] | Vista Ridge Apartments [Member]
Carrying value		$ 10,015	10,122
Effective Interest Rate		4.00%
Maturity Date		Aug. 01, 2053
Mortgages and Notes Payable [Member] | Windmill Farms Land [Member]
Carrying value		$ 12,391	$ 13,830
Effective Interest Rate		6.00%
Maturity Date		Feb. 28, 2021

[1] On September 14, 2020, we paid off the loan in connection with the sale of the underlining property (See Note 7 - Real Estate Activity).

[2] On March 5, 2020, we acquired 49.2 acres of land in Kent, Ohio in exchange for the note payable.

[3] We are currently negotiating an extension of the loan with the lender.

[4] On July 16, 2020, the loan was assumed by a third party in connection with the sale of the underlying property (See Note 7 - Real Estate Activity).

[5] The loan bears interest at prime rate plus 0.5%.

[6] On May 1, 2020, the loan was assumed by a third party in connection to sale of the underlying property (See Note 7 - Real Estate Activity).