FAIR VALUES OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets:
Non-mortgage loans receivable, net	$ 52,664	$ 37,926
Liabilities:
Redeemable OP unitholder interests	201,100	188,500
Government-sponsored pooled loan investments (1)
Assets:
Government-sponsored pooled loan investments	64,556	63,679
Carrying Amount
Assets:
Cash and cash equivalents	89,279	53,023
Secured loans receivable, net	757,107	793,433
Non-mortgage loans receivable, net	52,664	37,926
Liabilities:
Senior notes payable and other debt, gross	11,317,837	11,271,020
Derivative instruments and other liabilities	4,118	2,696
Redeemable OP unitholder interests	201,113	188,546
Carrying Amount | Government-sponsored pooled loan investments (1)
Assets:
Government-sponsored pooled loan investments	64,556	63,679
Fair Value
Assets:
Cash and cash equivalents	89,279	53,023
Secured loans receivable, net	776,410	816,849
Non-mortgage loans receivable, net	53,736	38,806
Liabilities:
Senior notes payable and other debt, gross	11,832,430	11,384,880
Derivative instruments and other liabilities	4,118	2,696
Redeemable OP unitholder interests	201,113	188,546
Fair Value | Government-sponsored pooled loan investments (1)
Assets:
Government-sponsored pooled loan investments	$ 64,556	$ 63,679