SCHEDULE III REAL ESTATE ASSETS AND ACCUMULATED DEPRECIATION AND AMORTIZATION (Schedule) (Details) $ in Thousands		12 Months Ended
	Sep. 07, 2016 USD ($) unit	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Real Estate and Accumulated Depreciation [Line Items]
Gross Amount at which Carried at Close of Period, Total		$ 574,684	$ 1,227,207	$ 914,074	$ 919,259
Accumulated Depreciation and Amortization		(41,817)	$ (120,176)	$ (91,560)	$ (64,171)
Aggregate cost of real estate for federal income tax purposes		607,200
Debt, outstanding amount		611,694
Subsidiary of Common Parent
Real Estate and Accumulated Depreciation [Line Items]
Interest rate on Class A non-voting preferred membership units	10.00%
Proceeds from sale of units	$ 800
Disposed of by Sale | Subsidiary of Common Parent
Real Estate and Accumulated Depreciation [Line Items]
Number of real estate units | unit	820
Mortgages
Real Estate and Accumulated Depreciation [Line Items]
Debt, outstanding amount		36,900
Properties Held for Investment [Member]
Real Estate and Accumulated Depreciation [Line Items]
Initial Cost to Company, Land		141,651
Initial Cost to Company, Building and Improvements		391,720
Initial Cost to Company, Total		533,371
Cost Capitalized Subsequent to Acquisition		41,313
Gross Amount at which Carried at Close of Period, Land		162,061
Gross Amount at which Carried at Close of Period, Building and Improvements		412,623
Gross Amount at which Carried at Close of Period, Total		574,684
Accumulated Depreciation and Amortization		(41,817)
Properties Held for Investment [Member] | Total Richardson Portfolio
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		36,886
Initial Cost to Company, Land		5,107
Initial Cost to Company, Building and Improvements		30,998
Initial Cost to Company, Total		36,105
Cost Capitalized Subsequent to Acquisition		6,368
Gross Amount at which Carried at Close of Period, Land		6,244
Gross Amount at which Carried at Close of Period, Building and Improvements		36,229
Gross Amount at which Carried at Close of Period, Total		42,473
Accumulated Depreciation and Amortization		$ (9,043)
Properties Held for Investment [Member] | Palisades Central I
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Initial Cost to Company, Land		$ 1,037
Initial Cost to Company, Building and Improvements		8,628
Initial Cost to Company, Total		9,665
Cost Capitalized Subsequent to Acquisition		2,342
Gross Amount at which Carried at Close of Period, Land		1,037
Gross Amount at which Carried at Close of Period, Building and Improvements		10,970
Gross Amount at which Carried at Close of Period, Total		12,007
Accumulated Depreciation and Amortization		$ (2,268)
Original Date of Construction		1980
Date Acquired or Foreclosed on		Nov. 23, 2011
Properties Held for Investment [Member] | Palisades Central II
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Initial Cost to Company, Land		$ 810
Initial Cost to Company, Building and Improvements		17,117
Initial Cost to Company, Total		17,927
Cost Capitalized Subsequent to Acquisition		1,165
Gross Amount at which Carried at Close of Period, Land		810
Gross Amount at which Carried at Close of Period, Building and Improvements		18,282
Gross Amount at which Carried at Close of Period, Total		19,092
Accumulated Depreciation and Amortization		$ (4,144)
Original Date of Construction		1985
Date Acquired or Foreclosed on		Nov. 23, 2011
Properties Held for Investment [Member] | Greenway I
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Initial Cost to Company, Land		$ 561
Initial Cost to Company, Building and Improvements		1,170
Initial Cost to Company, Total		1,731
Cost Capitalized Subsequent to Acquisition		1,194
Gross Amount at which Carried at Close of Period, Land		561
Gross Amount at which Carried at Close of Period, Building and Improvements		2,364
Gross Amount at which Carried at Close of Period, Total		2,925
Accumulated Depreciation and Amortization		$ (841)
Original Date of Construction		1983
Date Acquired or Foreclosed on		Nov. 23, 2011
Properties Held for Investment [Member] | Greenway III
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Initial Cost to Company, Land		$ 702
Initial Cost to Company, Building and Improvements		4,083
Initial Cost to Company, Total		4,785
Cost Capitalized Subsequent to Acquisition		530
Gross Amount at which Carried at Close of Period, Land		702
Gross Amount at which Carried at Close of Period, Building and Improvements		4,613
Gross Amount at which Carried at Close of Period, Total		5,315
Accumulated Depreciation and Amortization		$ (1,790)
Original Date of Construction		1983
Date Acquired or Foreclosed on		Nov. 23, 2011
Properties Held for Investment [Member] | Undeveloped Land
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Encumbrances		$ 0
Initial Cost to Company, Land		1,997
Initial Cost to Company, Building and Improvements		0
Initial Cost to Company, Total		1,997
Cost Capitalized Subsequent to Acquisition		1,137
Gross Amount at which Carried at Close of Period, Land		3,134
Gross Amount at which Carried at Close of Period, Building and Improvements		0
Gross Amount at which Carried at Close of Period, Total		3,134
Accumulated Depreciation and Amortization		$ 0
Date Acquired or Foreclosed on		Nov. 23, 2011
Properties Held for Investment [Member] | Park Highlands
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost to Company, Land		20,307
Initial Cost to Company, Building and Improvements		0
Initial Cost to Company, Total		20,307
Cost Capitalized Subsequent to Acquisition		14,121
Gross Amount at which Carried at Close of Period, Land		34,428
Gross Amount at which Carried at Close of Period, Building and Improvements		0
Gross Amount at which Carried at Close of Period, Total		34,428
Accumulated Depreciation and Amortization		$ 0
Date Acquired or Foreclosed on		Dec. 30, 2011
Properties Held for Investment [Member] | Burbank Collection
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Encumbrances		$ 10,958
Initial Cost to Company, Land		4,175
Initial Cost to Company, Building and Improvements		8,799
Initial Cost to Company, Total		12,974
Cost Capitalized Subsequent to Acquisition		4,462
Gross Amount at which Carried at Close of Period, Land		4,175
Gross Amount at which Carried at Close of Period, Building and Improvements		13,261
Gross Amount at which Carried at Close of Period, Total		17,436
Accumulated Depreciation and Amortization		$ (2,389)
Original Date of Construction		2008
Date Acquired or Foreclosed on		Dec. 12, 2012
Properties Held for Investment [Member] | Park Centre
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 9,877
Initial Cost to Company, Land		3,251
Initial Cost to Company, Building and Improvements		27,941
Initial Cost to Company, Total		31,192
Cost Capitalized Subsequent to Acquisition		(1,554)
Gross Amount at which Carried at Close of Period, Land		3,251
Gross Amount at which Carried at Close of Period, Building and Improvements		26,387
Gross Amount at which Carried at Close of Period, Total		29,638
Accumulated Depreciation and Amortization		$ (3,703)
Original Date of Construction		2000
Date Acquired or Foreclosed on		Mar. 28, 2013
Properties Held for Investment [Member] | Central Building
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 27,600
Initial Cost to Company, Land		7,015
Initial Cost to Company, Building and Improvements		26,124
Initial Cost to Company, Total		33,139
Cost Capitalized Subsequent to Acquisition		2,169
Gross Amount at which Carried at Close of Period, Land		7,015
Gross Amount at which Carried at Close of Period, Building and Improvements		28,293
Gross Amount at which Carried at Close of Period, Total		35,308
Accumulated Depreciation and Amortization		$ (4,663)
Original Date of Construction		1907
Date Acquired or Foreclosed on		Jul. 10, 2013
Properties Held for Investment [Member] | 1180 Raymond
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 31,000
Initial Cost to Company, Land		8,292
Initial Cost to Company, Building and Improvements		37,651
Initial Cost to Company, Total		45,943
Cost Capitalized Subsequent to Acquisition		452
Gross Amount at which Carried at Close of Period, Land		8,292
Gross Amount at which Carried at Close of Period, Building and Improvements		38,103
Gross Amount at which Carried at Close of Period, Total		46,395
Accumulated Depreciation and Amortization		$ (5,283)
Original Date of Construction		1929
Date Acquired or Foreclosed on		Aug. 20, 2013
Properties Held for Investment [Member] | Park Highlands II
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 0
Initial Cost to Company, Land		20,118
Initial Cost to Company, Building and Improvements		0
Initial Cost to Company, Total		20,118
Cost Capitalized Subsequent to Acquisition		4,830
Gross Amount at which Carried at Close of Period, Land		24,948
Gross Amount at which Carried at Close of Period, Building and Improvements		0
Gross Amount at which Carried at Close of Period, Total		24,948
Accumulated Depreciation and Amortization		$ 0
Date Acquired or Foreclosed on		Dec. 10, 2013
Properties Held for Investment [Member] | 424 Bedford
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Encumbrances		$ 24,282
Initial Cost to Company, Land		8,860
Initial Cost to Company, Building and Improvements		24,820
Initial Cost to Company, Total		33,680
Cost Capitalized Subsequent to Acquisition		887
Gross Amount at which Carried at Close of Period, Land		8,860
Gross Amount at which Carried at Close of Period, Building and Improvements		25,707
Gross Amount at which Carried at Close of Period, Total		34,567
Accumulated Depreciation and Amortization		$ (2,810)
Original Date of Construction		2010
Date Acquired or Foreclosed on		Jan. 31, 2014
Properties Held for Investment [Member] | Richardson Land II
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		90.00%
Encumbrances		$ 0
Initial Cost to Company, Land		3,096
Initial Cost to Company, Building and Improvements		0
Initial Cost to Company, Total		3,096
Cost Capitalized Subsequent to Acquisition		322
Gross Amount at which Carried at Close of Period, Land		3,418
Gross Amount at which Carried at Close of Period, Building and Improvements		0
Gross Amount at which Carried at Close of Period, Total		3,418
Accumulated Depreciation and Amortization		$ 0
Date Acquired or Foreclosed on		Sep. 04, 2014
Properties Held for Investment [Member] | Westpark Portfolio
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 85,200
Initial Cost to Company, Land		36,085
Initial Cost to Company, Building and Improvements		90,227
Initial Cost to Company, Total		126,312
Cost Capitalized Subsequent to Acquisition		6,710
Gross Amount at which Carried at Close of Period, Land		36,085
Gross Amount at which Carried at Close of Period, Building and Improvements		96,937
Gross Amount at which Carried at Close of Period, Total		133,022
Accumulated Depreciation and Amortization		$ (8,730)
Original Date of Construction		1984-1992
Date Acquired or Foreclosed on		May 10, 2016
Properties Held for Investment [Member] | Crown Pointe
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 50,500
Initial Cost to Company, Land		22,590
Initial Cost to Company, Building and Improvements		62,610
Initial Cost to Company, Total		85,200
Cost Capitalized Subsequent to Acquisition		2,629
Gross Amount at which Carried at Close of Period, Land		22,590
Gross Amount at which Carried at Close of Period, Building and Improvements		65,239
Gross Amount at which Carried at Close of Period, Total		87,829
Accumulated Depreciation and Amortization		$ (3,921)
Original Date of Construction		1985/1989
Date Acquired or Foreclosed on		Feb. 14, 2017
Properties Held for Investment [Member] | 125 John Carpenter
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent		100.00%
Encumbrances		$ 50,130
Initial Cost to Company, Land		2,755
Initial Cost to Company, Building and Improvements		82,550
Initial Cost to Company, Total		85,305
Cost Capitalized Subsequent to Acquisition		(83)
Gross Amount at which Carried at Close of Period, Land		2,755
Gross Amount at which Carried at Close of Period, Building and Improvements		82,467
Gross Amount at which Carried at Close of Period, Total		85,222
Accumulated Depreciation and Amortization		$ (1,275)
Original Date of Construction		1982/1983
Date Acquired or Foreclosed on		Sep. 15, 2017