Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting
Interest income	$ 16,191	$ 4,708	$ 28,858	$ 7,272
Interest expense	3,263	363	5,801	614
Net interest income	12,928	4,345	23,057	6,658
Expenses	5,798	1,406	11,220	2,212
Income (loss) from operations	7,130	2,939	11,837	4,446
Equity in earnings (losses) of unconsolidated ventures	5,827		9,042
Realized gain (loss) on investments and other		3,028		3,028
Unrealized gain (loss) on investments and other		(2,959)		(2,457)
Net income (loss)	12,957	3,008	20,879	5,017	15,304
Total Assets	1,523,922		1,523,922		859,938
Real Estate Debt
Segment Reporting
Interest income	14,737	4,293	26,462	6,390
Interest expense	3,222	150	5,712	175
Net interest income	11,515	4,143	20,750	6,215
Expenses	81	14	150	23
Income (loss) from operations	11,434	4,129	20,600	6,192
Equity in earnings (losses) of unconsolidated ventures	(181)		(181)
Net income (loss)	11,253	4,129	20,419	6,192
Total Assets	1,154,491		1,154,491		617,705
Equity Interests
Segment Reporting
Expenses	691		2,279
Income (loss) from operations	(691)		(2,279)
Equity in earnings (losses) of unconsolidated ventures	6,008		9,223
Net income (loss)	5,317		6,944
Total Assets	119,511		119,511
Real Estate Securities
Segment Reporting
Interest income	1,454	415	2,396	882
Interest expense	41	213	89	439
Net interest income	1,413	202	2,307	443
Expenses	7		14
Income (loss) from operations	1,406	202	2,293	443
Realized gain (loss) on investments and other		3,028		3,028
Unrealized gain (loss) on investments and other		(2,959)		(2,457)
Net income (loss)	1,406	271	2,293	1,014
Total Assets	55,676		55,676		29,712
Corporate
Segment Reporting
Expenses	5,019	1,392	8,777	2,189
Income (loss) from operations	(5,019)	(1,392)	(8,777)	(2,189)
Net income (loss)	(5,019)	(1,392)	(8,777)	(2,189)
Total Assets	$ 194,244		$ 194,244		$ 212,521