SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) item
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	188
Carrying amount of mortgages	$ 81,056
Principal amount of loans subject to deliquent principal or interest	$ 130
SBA 7(a) Loans
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	187
Carrying amount of mortgages	$ 80,632
Principal amount of loans subject to deliquent principal or interest	130
Loans not secured by real estate	114
Loans with subordinate lien positions	267
Federal income tax cost basis of mortgage loans (unaudited)	58,778
SBA 7(a) Loans | Government guaranteed portions
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Carrying amount of mortgages	10,623
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | SBA 7(a) loans receivable, subject to secured borrowings
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Carrying amount of mortgages	20,691
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | General reserves
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Reserves	(333)
Principal amount of loans subject to deliquent principal or interest	$ 0
SBA 7(a) Loans | Indiana
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	25
Carrying amount of mortgages	$ 10,074
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Indiana | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 40
Interest Rate	5.75%
SBA 7(a) Loans | Indiana | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 1,230
Interest Rate	7.00%
SBA 7(a) Loans | Ohio
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	25
Size of loans	$ 0
Carrying amount of mortgages	7,863
Principal amount of loans subject to deliquent principal or interest	$ 0
SBA 7(a) Loans | Ohio | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Interest Rate	6.00%
SBA 7(a) Loans | Ohio | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 820
Interest Rate	7.00%
SBA 7(a) Loans | Michigan
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	21
Carrying amount of mortgages	$ 5,495
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Michigan | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 10
Interest Rate	6.00%
SBA 7(a) Loans | Michigan | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 540
Interest Rate	7.00%
SBA 7(a) Loans | Texas
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	25
Carrying amount of mortgages	$ 4,703
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Texas | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 0
Interest Rate	5.13%
SBA 7(a) Loans | Texas | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 650
Interest Rate	7.00%
SBA 7(a) Loans | Virginia
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	8
Carrying amount of mortgages	$ 2,806
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Virginia | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 40
Interest Rate	5.75%
SBA 7(a) Loans | Virginia | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 790
Interest Rate	7.00%
SBA 7(a) Loans | South Carolina
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	6
Carrying amount of mortgages	$ 1,671
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | South Carolina | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 0
Interest Rate	6.00%
SBA 7(a) Loans | South Carolina | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 800
Interest Rate	7.00%
SBA 7(a) Loans | Illinois
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	5
Carrying amount of mortgages	$ 1,536
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Illinois | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 60
Interest Rate	6.00%
SBA 7(a) Loans | Illinois | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 640
Interest Rate	7.00%
SBA 7(a) Loans | Florida
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	8
Carrying amount of mortgages	$ 1,499
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Florida | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 0
Interest Rate	6.25%
SBA 7(a) Loans | Florida | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 350
Interest Rate	7.00%
SBA 7(a) Loans | Alabama
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	6
Carrying amount of mortgages	$ 1,455
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Alabama | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 40
Interest Rate	6.00%
SBA 7(a) Loans | Alabama | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 450
Interest Rate	7.00%
SBA 7(a) Loans | Missouri
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	5
Carrying amount of mortgages	$ 1,429
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Missouri | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 40
Interest Rate	6.00%
SBA 7(a) Loans | Missouri | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 600
Interest Rate	7.00%
SBA 7(a) Loans | Kentucky
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	6
Carrying amount of mortgages	$ 1,270
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Kentucky | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 100
Interest Rate	6.25%
SBA 7(a) Loans | Kentucky | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 390
Interest Rate	7.00%
SBA 7(a) Loans | Pennsylvania
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	3
Carrying amount of mortgages	$ 1,172
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Pennsylvania | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 320
Interest Rate	6.25%
SBA 7(a) Loans | Pennsylvania | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 520
Interest Rate	7.00%
SBA 7(a) Loans | Wisconsin
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	8
Carrying amount of mortgages	$ 1,142
Principal amount of loans subject to deliquent principal or interest	130
SBA 7(a) Loans | Wisconsin | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 0
Interest Rate	6.00%
SBA 7(a) Loans | Wisconsin | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 290
Interest Rate	7.00%
SBA 7(a) Loans | North Carolina
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	3
Carrying amount of mortgages	$ 1,040
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | North Carolina | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 80
Interest Rate	6.75%
SBA 7(a) Loans | North Carolina | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 650
Interest Rate	7.00%
SBA 7(a) Loans | Georgia
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	5
Carrying amount of mortgages	$ 1,019
Principal amount of loans subject to deliquent principal or interest	0
SBA 7(a) Loans | Georgia | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 80
Interest Rate	6.50%
SBA 7(a) Loans | Georgia | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 370
Interest Rate	7.00%
SBA 7(a) Loans | Other
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	28
Carrying amount of mortgages	$ 5,477
Principal amount of loans subject to deliquent principal or interest	$ 0
SBA 7(a) Loans | Other | Minimum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Interest Rate	5.75%
SBA 7(a) Loans | Other | Maximum
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 560
Interest Rate	7.00%
Conventional Loans | North Carolina
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Number of loans | item	1
Size of loans	$ 430
Interest Rate	7.50%
Carrying amount of mortgages	$ 424
Principal amount of loans subject to deliquent principal or interest	0
Mortgage Loans - $387,000 | SBA 7(a) Loans | Kentucky
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 387
Interest Rate	6.50%
Mortgage Loans - $130,000 | SBA 7(a) Loans | Wisconsin
SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE
Size of loans	$ 130
Interest Rate	6.25%
Reserves	$ (129)