LOANS RECEIVABLE AND INVESTMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable
Total investments reported as Secured loans receivable and investments, net, carrying amount	$ 1,212,519	$ 1,346,359
Total investments reported as Secured loans receivable and investments, net, amortized cost	1,211,889	1,345,557
Total investments reported as Secured loans receivable and investments, net, fair value	1,213,868	1,340,987
Total investments reported as Secured loans receivable and investments, net, unrealized gain	630	802
Total loans receivable and investments, net, carrying amount	1,268,644	1,406,216
Total loans receivable and investments, net, amortized cost	1,268,014	1,405,414
Total loans receivable and investments, net, fair value	1,270,332	1,399,836
Total loans receivable and investments, net, unrealized gain	630	802
Secured/ Mortgage Loans and Other
Accounts, Notes, Loans and Financing Receivable
Total investments reported as Secured loans receivable and investments, net, unrealized gain	0	0
Total loans receivable and investments, net, unrealized gain	0	0
Secured/mortgage loans and other, net, carrying amount	1,157,638	1,291,694
Secured/mortgage loans and other, net, amortized cost	1,157,638	1,291,694
Secured/mortgage loans and other, net, fair value	1,158,987	1,286,322
Non-Mortgage Loans Receivable, Net
Accounts, Notes, Loans and Financing Receivable
Total investments reported as Secured loans receivable and investments, net, unrealized gain	0	0
Total loans receivable and investments, net, unrealized gain	0	0
Non-mortgage loans receivable, net, carrying amount	56,125	59,857
Non-mortgage loans receivable, net, amortized cost	56,125	59,857
Non-mortgage loans receivable, net, fair value	56,464	58,849
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Accounts, Notes, Loans and Financing Receivable
Total investments reported as Secured loans receivable and investments, net, unrealized gain	630	802
Total loans receivable and investments, net, unrealized gain	630	802
Government-sponsored pooled loan investments, net, carrying amount and fair value	54,881	54,665
Government-sponsored pooled loan investments, amortized cost	$ 54,251	$ 53,863