Equity Investments (Details 4) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 131,448	$ 97,682	$ 79,526	$ 40,952
TOTAL ASSETS	919,077	923,163
LIABILITIES AND MEMBERS' CAPITAL
TOTAL LIABILITIES AND EQUITY	919,077	923,163
RE CDO Management LLC [Member]
ASSETS
Cash and cash equivalents	205	123
Loan receivable	1,062	1,070
Receivables and other assets	947	2,400
TOTAL ASSETS	2,214	3,593
LIABILITIES AND MEMBERS' CAPITAL
Other liabilities	18	36
Members' Capital	2,196	3,557
TOTAL LIABILITIES AND EQUITY	2,214	3,593
Carrying value of the Trust's investments in RE CDO Management	$ 1,098	$ 1,779