DEBT - Schedule (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt
Total Debt	$ 641,257,000	$ 630,852,000
Mortgages Payable
Debt
Gross debt	416,300,000	416,300,000
Deferred loan costs	(1,494,000)	(1,540,000)
Total Debt	414,806,000	414,760,000
Mortgage loan with a fixed interest of 4.14% per annum, due on July 1, 2026
Debt
Gross debt	$ 370,300,000	370,300,000
Fixed interest rate	4.14%
Amount of balance due on maturity	$ 370,300,000
Mortgage loan with a fixed interest of 4.50% per annum, due on January 5, 2027
Debt
Gross debt	$ 46,000,000	46,000,000
Fixed interest rate	4.50%
Period of amortization schedule	10 years
Amount of balance due on maturity	$ 42,008,000
Secured Borrowings - Government Guaranteed Loans
Debt
Gross debt	20,954,000	20,691,000
Premiums and discounts	1,412,000	1,466,000
Total Debt	22,366,000	22,157,000
Secured borrowing principal on SBA 7(a) loans sold for a premium and excess spread—variable rate, reset quarterly, based on prime rate with weighted average coupon rate of 5.10% and 4.85% at March 31, 2018 and December 31, 2017, respectively.
Debt
Gross debt	$ 16,347,000	$ 16,812,000
Weighted average rate	5.10%	4.85%
Secured borrowing principal on SBA 7(a) loans sold for excess spread—variable rate, reset quarterly, based on prime rate with weighted average coupon rate of 2.82% and 2.60% at March 31, 2018 and December 31, 2017, respectively.
Debt
Gross debt	$ 4,607,000	$ 3,879,000
Weighted average rate	2.82%	2.60%
Other Debt
Debt
Gross debt	$ 207,070,000	$ 197,070,000
Total Debt	204,085,000	193,935,000
Unsecured term loan facility
Debt
Gross debt	170,000,000	170,000,000
Junior subordinated notes
Debt
Gross debt	27,070,000	27,070,000
Premiums and discounts	$ (1,917,000)	(1,937,000)
Junior subordinated notes | LIBOR
Debt
Interest rate margin	3.25%
Unsecured credit facilities
Debt
Gross debt	$ 10,000,000	0
Unsecured term loan and credit facilities
Debt
Deferred loan costs	$ (1,068,000)	$ (1,198,000)