FAIR VALUES OF FINANCIAL INSTRUMENTS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Assets:
Secured loans receivable and investments, net	$ 470,441	$ 635,002
Unsecured loans receivable, net	44,105	62,118
Liabilities:
Redeemable OP unitholder interests	123,100	114,900
Carrying Amount
Assets:
Cash and cash equivalents	62,421	67,908
Secured loans receivable and investments, net	449,353	635,002
Unsecured loans receivable, net	44,105	62,118
Marketable Securities	21,088	5,400
Liabilities:
Senior notes payable and other debt, gross	8,362,709	8,186,315
Derivative instruments and other liabilities	23,675	45,966
Redeemable OP unitholder interests	123,075	114,933
Fair Value
Assets:
Cash and cash equivalents	62,421	67,908
Secured loans receivable and investments, net	449,806	636,714
Unsecured loans receivable, net	45,991	65,146
Available-for-sale Securities, Fair Value Disclosure	21,088	5,400
Liabilities:
Senior notes payable and other debt, gross	8,446,639	8,600,450
Derivative instruments and other liabilities	23,675	45,966
Redeemable OP unitholder interests	$ 123,075	$ 114,933