LOANS RECEIVABLE AND INVESTMENTS - Narrative 2 (Details)	1 Months Ended		3 Months Ended		12 Months Ended
	Feb. 29, 2016 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) loan	Dec. 31, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in loans receivable and other			$ 146,214,000	$ 39,573,000
Debt instrument, face amount	$ 200,000,000
Proceeds from sale of loans					$ 97,000,000
Gain on repayment of loans receivable					$ 1,900,000
Unsecured Debt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan					1
Debt instrument, face amount					$ 20,000,000.0
Secured Debt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan					1
Debt instrument, face amount					$ 78,400,000.0
Secured mortgage loans and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in loans receivable and other	$ 140,000,000
Secured loan, stated interest rate, percentage	9.95%
Number Of Loans Sold | loan					3
Non-mortgage loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number Of Loans Sold | loan					1
Corporate Debt Securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Available-for-sale Securities, amortized cost basis		$ 71,000,000
Proceeds from sale of investment		76,800,000
Recognized gain on sale of investments		$ 5,800,000
Unrealized gain on investment						$ 5,000,000