COMMERCIAL REAL ESTATE INVESTMENTS - Total Commercial Real Estate Held for Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2017		Dec. 31, 2016
Real estate held for investment, at amortized cost
Real estate held for investment, at amortized cost	$ 441,971		$ 448,620
Less: accumulated depreciation	(48,920)		(34,221)
Total real estate held for investment, at amortized cost, net	393,051		414,399
Equity in unconsolidated joint ventures	92,902		60,168
Investments in commercial real estate, net	485,953	[1]	474,567
Land
Real estate held for investment, at amortized cost
Real estate held for investment, at amortized cost	111,012		112,675
Buildings and improvements
Real estate held for investment, at amortized cost
Real estate held for investment, at amortized cost	$ 330,959		$ 335,945

[1] As a result of a change to a clearing organization’s rulebook effective January 3, 2017, beginning with the first quarter 2017 and in subsequent periods the Company is presenting the fair value of centrally cleared interest rate swaps net of variation margin pledged under such transactions. The variation margin was previously reported under cash and cash equivalents and is currently reported as a reduction to interest rate swaps, at fair value. Balances reported prior to the effective date will not be adjusted.