SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gross Amounts of Which Carried at End of Year Total	$ 477,963	$ 463,732	$ 1,165,662	$ 1,066,603
Accumulated Depreciation	90,173	$ 79,228	$ 177,546	$ 165,597
Properties Held for Investment/Corporate Debt [Member]
Encumbrances	236,685
Initial Cost Land	136,552
Initial Cost Buildings	284,089
Cost Capitalized Subsequent to Acquisition Improvements	88,386
Asset Impairment	(31,064)
Gross Amounts of Which Carried at End of Year Land	136,552
Gross Amounts of Which Carried at End of Year Building & Improvements	341,411
Gross Amounts of Which Carried at End of Year Total	477,963
Accumulated Depreciation	90,173
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member]
Encumbrances	120,024
Initial Cost Land	15,981
Initial Cost Buildings	135,766
Cost Capitalized Subsequent to Acquisition Improvements	4,426
Gross Amounts of Which Carried at End of Year Land	15,981
Gross Amounts of Which Carried at End of Year Building & Improvements	140,192
Gross Amounts of Which Carried at End of Year Total	156,173
Accumulated Depreciation	10,562
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Legacy at Pleasant Grove, Texarkana [Member] | TEXAS
Encumbrances	13,944
Initial Cost Land	2,005
Initial Cost Buildings	17,892
Cost Capitalized Subsequent to Acquisition Improvements	217
Gross Amounts of Which Carried at End of Year Land	2,005
Gross Amounts of Which Carried at End of Year Building & Improvements	18,109
Gross Amounts of Which Carried at End of Year Total	20,114
Accumulated Depreciation	$ 2,289
Date of Construction	2006
Date Acquired	12/14
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Toulon, Gautier [Member] | MISSISSIPPI
Encumbrances	$ 19,575
Initial Cost Land	1,621
Initial Cost Buildings	20,107
Cost Capitalized Subsequent to Acquisition Improvements	372
Gross Amounts of Which Carried at End of Year Land	1,621
Gross Amounts of Which Carried at End of Year Building & Improvements	20,479
Gross Amounts of Which Carried at End of Year Total	22,100
Accumulated Depreciation	$ 4,273
Date of Construction	2011
Date Acquired	09/09
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Villager, Ft. Walton [Member] | FLORIDA
Encumbrances	$ 672
Initial Cost Land	141
Initial Cost Buildings	1,267
Gross Amounts of Which Carried at End of Year Land	141
Gross Amounts of Which Carried at End of Year Building & Improvements	1,267
Gross Amounts of Which Carried at End of Year Total	1,408
Accumulated Depreciation	$ 148
Date of Construction	1972
Date Acquired	06/15
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Villas at Bon Secour, Gulf Shores [Member] | ALABAMA
Encumbrances	$ 11,212
Initial Cost Land	2,715
Initial Cost Buildings	15,385
Gross Amounts of Which Carried at End of Year Land	2,715
Gross Amounts of Which Carried at End of Year Building & Improvements	15,385
Gross Amounts of Which Carried at End of Year Total	18,100
Accumulated Depreciation	$ 545
Date of Construction	2007
Date Acquired	07/18
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Vista Ridge, Tupelo [Member] | MISSISSIPPI
Encumbrances	$ 10,252
Initial Cost Land	1,339
Initial Cost Buildings	13,398
Gross Amounts of Which Carried at End of Year Land	1,339
Gross Amounts of Which Carried at End of Year Building & Improvements	13,398
Gross Amounts of Which Carried at End of Year Total	14,737
Accumulated Depreciation	$ 1,893
Date of Construction	2009
Date Acquired	10/15
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Chelsea, Beaumont [Member] | TEXAS
Encumbrances	$ 8,794
Initial Cost Land	1,225
Initial Cost Buildings	11,025
Cost Capitalized Subsequent to Acquisition Improvements	160
Gross Amounts of Which Carried at End of Year Land	1,225
Gross Amounts of Which Carried at End of Year Building & Improvements	11,185
Gross Amounts of Which Carried at End of Year Total	12,410
Accumulated Depreciation	$ 303
Date of Construction	1999
Date Acquired	11/18
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Overlook at Allensville Square II, Sevierville [Member] | TENNESSEE
Encumbrances	$ 15,829
Initial Cost Land	2,411
Initial Cost Buildings	17,005
Gross Amounts of Which Carried at End of Year Land	2,411
Gross Amounts of Which Carried at End of Year Building & Improvements	17,005
Gross Amounts of Which Carried at End of Year Total	19,416
Accumulated Depreciation	$ 319
Date of Construction	2012
Date Acquired	11/15
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Landing, Houma [Member] | LOUISIANA
Encumbrances	$ 15,484
Initial Cost Land	2,012
Initial Cost Buildings	18,115
Cost Capitalized Subsequent to Acquisition Improvements	25
Gross Amounts of Which Carried at End of Year Land	2,012
Gross Amounts of Which Carried at End of Year Building & Improvements	18,140
Gross Amounts of Which Carried at End of Year Total	20,152
Accumulated Depreciation	$ 491
Date of Construction	2005
Date Acquired	12/18
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Farnham Park, Port Aurther [Member] | TEXAS
Encumbrances	$ 9,183
Initial Cost Land	1,010
Initial Cost Buildings	9,086
Cost Capitalized Subsequent to Acquisition Improvements	144
Gross Amounts of Which Carried at End of Year Land	1,010
Gross Amounts of Which Carried at End of Year Building & Improvements	9,230
Gross Amounts of Which Carried at End of Year Total	10,240
Accumulated Depreciation	$ 251
Date of Construction	1999
Date Acquired	11/18
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Properties Held for Investment Apartments [Member] | Parc at Denham Springs Phase II, Denham Springs [Member] | LOUISIANA
Encumbrances	$ 15,079
Initial Cost Land	1,502
Initial Cost Buildings	12,486
Cost Capitalized Subsequent to Acquisition Improvements	3,508
Gross Amounts of Which Carried at End of Year Land	1,502
Gross Amounts of Which Carried at End of Year Building & Improvements	15,994
Gross Amounts of Which Carried at End of Year Total	17,496
Accumulated Depreciation	$ 50
Date of Construction	2010
Date Acquired	11/9
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Apartments Under Construction [Member]
Encumbrances	$ 9,017
Initial Cost Land	10,195
Cost Capitalized Subsequent to Acquisition Improvements	12,168
Gross Amounts of Which Carried at End of Year Land	10,195
Gross Amounts of Which Carried at End of Year Building & Improvements	12,168
Gross Amounts of Which Carried at End of Year Total	22,363
Properties Held for Investment/Corporate Debt [Member] | Apartments Under Construction [Member] | Forest Pines [Member] | TEXAS
Initial Cost Land	5,040
Cost Capitalized Subsequent to Acquisition Improvements	301
Gross Amounts of Which Carried at End of Year Land	5,040
Gross Amounts of Which Carried at End of Year Building & Improvements	301
Gross Amounts of Which Carried at End of Year Total	5,341
Properties Held for Investment/Corporate Debt [Member] | Apartments Under Construction [Member] | Sugar Mill III, Addis [Member] | LOUISIANA
Encumbrances	6,302
Initial Cost Land	576
Cost Capitalized Subsequent to Acquisition Improvements	7,023
Gross Amounts of Which Carried at End of Year Land	576
Gross Amounts of Which Carried at End of Year Building & Improvements	7,023
Gross Amounts of Which Carried at End of Year Total	$ 7,599
Date Acquired	11/15
Properties Held for Investment/Corporate Debt [Member] | Apartments Under Construction [Member] | McKinney Apts at Heritage, McKinney [Member] | TEXAS
Initial Cost Land	$ 2,481
Cost Capitalized Subsequent to Acquisition Improvements	89
Gross Amounts of Which Carried at End of Year Land	2,481
Gross Amounts of Which Carried at End of Year Building & Improvements	89
Gross Amounts of Which Carried at End of Year Total	$ 2,570
Date Acquired	6/17
Properties Held for Investment/Corporate Debt [Member] | Apartments Under Construction [Member] | Forest Pines Phase II (Forest Grove), Bryan [Member] | TEXAS
Encumbrances	$ 1,560
Cost Capitalized Subsequent to Acquisition Improvements	4,674
Gross Amounts of Which Carried at End of Year Building & Improvements	4,674
Gross Amounts of Which Carried at End of Year Total	$ 4,674
Date Acquired	4/19
Properties Held for Investment/Corporate Debt [Member] | Apartments Under Construction [Member] | LD Athens Lindsay Ln, Athens [Member] | LOUISIANA
Encumbrances	$ 1,155
Initial Cost Land	2,098
Cost Capitalized Subsequent to Acquisition Improvements	81
Gross Amounts of Which Carried at End of Year Land	2,098
Gross Amounts of Which Carried at End of Year Building & Improvements	81
Gross Amounts of Which Carried at End of Year Total	$ 2,179
Date Acquired	9/19
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member]
Encumbrances	$ 92,838
Initial Cost Land	33,533
Initial Cost Buildings	148,323
Cost Capitalized Subsequent to Acquisition Improvements	57,168
Asset Impairment	(9,600)
Gross Amounts of Which Carried at End of Year Land	33,533
Gross Amounts of Which Carried at End of Year Building & Improvements	195,891
Gross Amounts of Which Carried at End of Year Total	229,424
Accumulated Depreciation	79,611
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | 600 Las Colinass, Las Colinas [Member] | TEXAS
Encumbrances	37,215
Initial Cost Land	5,751
Initial Cost Buildings	51,759
Cost Capitalized Subsequent to Acquisition Improvements	20,143
Gross Amounts of Which Carried at End of Year Land	5,751
Gross Amounts of Which Carried at End of Year Building & Improvements	71,902
Gross Amounts of Which Carried at End of Year Total	77,653
Accumulated Depreciation	$ 32,858
Date of Construction	1984
Date Acquired	08/05
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | 770 South Post Oak, Houston [Member] | TEXAS
Encumbrances	$ 12,178
Initial Cost Land	1,763
Initial Cost Buildings	15,834
Cost Capitalized Subsequent to Acquisition Improvements	697
Gross Amounts of Which Carried at End of Year Land	1,763
Gross Amounts of Which Carried at End of Year Building & Improvements	16,531
Gross Amounts of Which Carried at End of Year Total	18,294
Accumulated Depreciation	$ 2,117
Date of Construction	1970
Date Acquired	07/15
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | Bridgeview Plaza, LaCrosse [Member] | WISCONSIN
Encumbrances	$ 3,908
Cost Capitalized Subsequent to Acquisition Improvements	1,207
Gross Amounts of Which Carried at End of Year Building & Improvements	1,207
Gross Amounts of Which Carried at End of Year Total	1,207
Accumulated Depreciation	$ 804
Date of Construction	1979
Date Acquired	03/03
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | Browning Place (Park West I), Farmers Branch [Member] | TEXAS
Initial Cost Land	$ 5,096
Initial Cost Buildings	45,868
Cost Capitalized Subsequent to Acquisition Improvements	26,645
Gross Amounts of Which Carried at End of Year Land	5,096
Gross Amounts of Which Carried at End of Year Building & Improvements	72,513
Gross Amounts of Which Carried at End of Year Total	77,609
Accumulated Depreciation	$ 29,867
Date of Construction	1984
Date Acquired	04/05
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | Fruitland Plaza, Fruitland Park [Member] | FLORIDA
Initial Cost Land	$ 23
Cost Capitalized Subsequent to Acquisition Improvements	83
Gross Amounts of Which Carried at End of Year Land	23
Gross Amounts of Which Carried at End of Year Building & Improvements	83
Gross Amounts of Which Carried at End of Year Total	106
Accumulated Depreciation	$ 71
Date Acquired	05/92
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | Senlac VHP, Farmers Branch [Member] | TEXAS
Initial Cost Land	$ 622
Cost Capitalized Subsequent to Acquisition Improvements	142
Gross Amounts of Which Carried at End of Year Land	622
Gross Amounts of Which Carried at End of Year Building & Improvements	142
Gross Amounts of Which Carried at End of Year Total	764
Accumulated Depreciation	$ 142
Date Acquired	08/05
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Commercial Held for Investment [Member] | Stanford Center, Dallas [Member] | TEXAS
Encumbrances	$ 39,537
Initial Cost Land	20,278
Initial Cost Buildings	34,862
Cost Capitalized Subsequent to Acquisition Improvements	8,251
Asset Impairment	(9,600)
Gross Amounts of Which Carried at End of Year Land	20,278
Gross Amounts of Which Carried at End of Year Building & Improvements	33,513
Gross Amounts of Which Carried at End of Year Total	53,791
Accumulated Depreciation	$ 13,752
Date Acquired	06/08
Life on Which Depreciation In Latest Statement of Operation is Computed	40 years
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Dedeaux, Gulfport [Member] | MISSISSIPPI
Initial Cost Land	$ 1,612
Cost Capitalized Subsequent to Acquisition Improvements	46
Asset Impairment	(38)
Gross Amounts of Which Carried at End of Year Land	1,612
Gross Amounts of Which Carried at End of Year Building & Improvements	8
Gross Amounts of Which Carried at End of Year Total	$ 1,620
Date Acquired	10/06
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Gautier Land, Gautier [Member] | MISSISSIPPI
Initial Cost Land	$ 202
Gross Amounts of Which Carried at End of Year Land	202
Gross Amounts of Which Carried at End of Year Total	$ 202
Date Acquired	07/98
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Lake Shore Villas, Humble [Member] | TEXAS
Initial Cost Land	$ 81
Cost Capitalized Subsequent to Acquisition Improvements	3
Gross Amounts of Which Carried at End of Year Land	81
Gross Amounts of Which Carried at End of Year Building & Improvements	3
Gross Amounts of Which Carried at End of Year Total	$ 84
Date Acquired	03/02
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Lubbock Land, Lubbock [Member] | TEXAS
Initial Cost Land	$ 234
Gross Amounts of Which Carried at End of Year Land	234
Gross Amounts of Which Carried at End of Year Total	$ 234
Date Acquired	01/04
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Ocean Estates, Gulfport [Member] | MISSISSIPPI
Initial Cost Land	$ 1,418
Cost Capitalized Subsequent to Acquisition Improvements	390
Gross Amounts of Which Carried at End of Year Land	1,418
Gross Amounts of Which Carried at End of Year Building & Improvements	390
Gross Amounts of Which Carried at End of Year Total	$ 1,808
Date Acquired	10/07
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Union Pacific Railroad Land, Dallas [Member] | TEXAS
Initial Cost Land	$ 130
Gross Amounts of Which Carried at End of Year Land	130
Gross Amounts of Which Carried at End of Year Total	$ 130
Date Acquired	03/04
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Willowick Land, Pensacola [Member] | FLORIDA
Initial Cost Land	$ 137
Gross Amounts of Which Carried at End of Year Land	137
Gross Amounts of Which Carried at End of Year Total	$ 137
Date Acquired	01/95
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Windmill Farms Land, Kaufman County [Member] | TEXAS
Date Acquired	11/11
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Windmill Farms Land, Kaufman County [Member] | TEXAS
Encumbrances	$ 13,861
Initial Cost Land	55,668
Cost Capitalized Subsequent to Acquisition Improvements	13,913
Asset Impairment	(20,343)
Gross Amounts of Which Carried at End of Year Land	55,668
Gross Amounts of Which Carried at End of Year Building & Improvements	(6,430)
Gross Amounts of Which Carried at End of Year Total	49,238
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | T Palm Desert, Riverside [Member] | CANADA
Initial Cost Land	1,800
Gross Amounts of Which Carried at End of Year Land	1,800
Gross Amounts of Which Carried at End of Year Total	$ 1,800
Date Acquired	9/19
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Lacy Longhorn Land, Farmers Branch [Member] | TEXAS
Date Acquired	06/04
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Lacy Longhorn Land, Farmers Branch [Member] | TEXAS
Initial Cost Land	$ 1,169
Cost Capitalized Subsequent to Acquisition Improvements	(760)
Gross Amounts of Which Carried at End of Year Land	1,169
Gross Amounts of Which Carried at End of Year Building & Improvements	(760)
Gross Amounts of Which Carried at End of Year Total	409
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Minivest Land, Dallas [Member] | TEXAS
Initial Cost Land	7
Gross Amounts of Which Carried at End of Year Land	7
Gross Amounts of Which Carried at End of Year Total	$ 7
Date Acquired	04/13
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Nicholson Croslin, Dallas [Member] | TEXAS
Date Acquired	10/98
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Nicholson Croslin, Dallas [Member] | TEXAS
Initial Cost Land	$ 184
Cost Capitalized Subsequent to Acquisition Improvements	(118)
Gross Amounts of Which Carried at End of Year Land	184
Gross Amounts of Which Carried at End of Year Building & Improvements	(118)
Gross Amounts of Which Carried at End of Year Total	$ 66
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Nicholson Mendoza, Dallas [Member] | TEXAS
Date Acquired	10/98
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Nicholson Mendoza, Dallas [Member] | TEXAS
Initial Cost Land	$ 80
Cost Capitalized Subsequent to Acquisition Improvements	(51)
Gross Amounts of Which Carried at End of Year Land	80
Gross Amounts of Which Carried at End of Year Building & Improvements	(51)
Gross Amounts of Which Carried at End of Year Total	29
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Mercer Crossing, Farmers Branch [Member] | TEXAS
Initial Cost Land	10,966
Asset Impairment	10,966
Gross Amounts of Which Carried at End of Year Building & Improvements	$ 10,966
Date Acquired	1/08
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | McKinney 36, Collin County [Member] | TEXAS
Encumbrances	$ 945
Initial Cost Land	635
Cost Capitalized Subsequent to Acquisition Improvements	161
Asset Impairment	(19)
Gross Amounts of Which Carried at End of Year Land	635
Gross Amounts of Which Carried at End of Year Building & Improvements	142
Gross Amounts of Which Carried at End of Year Total	$ 777
Date Acquired	01/98
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Travis Ranch Land, Kaufman County [Member] | TEXAS
Initial Cost Land	$ 80
Gross Amounts of Which Carried at End of Year Land	80
Gross Amounts of Which Carried at End of Year Total	$ 80
Date Acquired	08/08
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member] | Dominion Mercer Phase II Farmers Branch [Member] | TEXAS
Initial Cost Land	$ 2,440
Cost Capitalized Subsequent to Acquisition Improvements	111
Asset Impairment	(135)
Gross Amounts of Which Carried at End of Year Land	2,440
Gross Amounts of Which Carried at End of Year Building & Improvements	(24)
Gross Amounts of Which Carried at End of Year Total	$ 2,416
Date Acquired	3/99
Properties Held for Investment/Corporate Debt [Member] | Land Held for Investment [Member]
Encumbrances	$ 14,806
Initial Cost Land	76,843
Cost Capitalized Subsequent to Acquisition Improvements	14,624
Asset Impairment	(21,464)
Gross Amounts of Which Carried at End of Year Land	76,843
Gross Amounts of Which Carried at End of Year Building & Improvements	(6,840)
Gross Amounts of Which Carried at End of Year Total	$ 70,003