Fair Value (Details 3) (USD $)	Jun. 30, 2014 creditfacility	Dec. 31, 2013
Financial assets:
Real estate debt investments, net	$ 1,259,805,000	$ 1,074,773,000
Real estate debt investments, held for sale	0	17,500,000
Real estate securities, available for sale	70,500,000	66,450,000
Financial liabilities:
Securitization bonds payable	482,499,000	506,929,000
Credit facilities	169,283,000	28,323,000
Credit Facilities
Number of term credit facilities under which amounts are outstanding (credit facility)	5
Principal Amount
Financial assets:
Real estate debt investments, net	1,257,654,000	1,073,189,000
Real estate debt investments, held for sale	0	17,500,000
Real estate securities, available for sale	104,542,000	104,542,000
Financial liabilities:
Securitization bonds payable	482,593,000	507,359,000
Mortgage notes payable	131,603,000	102,500,000
Credit facilities	169,283,000	28,323,000
Future funding commitments related to real estate debt investments	59,300,000	44,600,000
Carrying Value
Financial assets:
Real estate debt investments, net	1,259,805,000	1,074,773,000
Real estate debt investments, held for sale	0	17,500,000
Real estate securities, available for sale	70,500,000	66,450,000
Financial liabilities:
Securitization bonds payable	482,499,000	506,929,000
Mortgage notes payable	131,603,000	102,500,000
Credit facilities	169,283,000	28,323,000
Fair Value
Financial assets:
Real estate debt investments, net	1,435,342,000	1,197,383,000
Real estate debt investments, held for sale	0	17,500,000
Real estate securities, available for sale	70,500,000	66,450,000
Financial liabilities:
Securitization bonds payable	482,475,000	507,212,000
Mortgage notes payable	131,830,000	102,500,000
Credit facilities	$ 169,283,000	$ 28,323,000