Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting
Interest income	$ 12,667	$ 2,564
Interest expense	2,538	250
Net interest income	10,129	2,314
Expenses	5,422	806
Income (loss) from operations	4,707	1,508
Equity in earnings (losses) of unconsolidated ventures	3,215
Unrealized gain (loss) on investments and other		502
Net income (loss)	7,922	2,010	15,304
Total Assets	1,069,240		859,938
Real Estate Debt
Segment Reporting
Interest income	11,725	2,097
Interest expense	2,490	25
Net interest income	9,235	2,072
Expenses	69	9
Income (loss) from operations	9,166	2,063
Net income (loss)	9,166	2,063
Total Assets	745,857		617,705
Real Estate Securities
Segment Reporting
Interest income	942	467
Interest expense	48	225
Net interest income	894	242
Expenses	7
Income (loss) from operations	887	242
Unrealized gain (loss) on investments and other		502
Net income (loss)	887	744
Total Assets	54,386		29,712
Preferred Equity
Segment Reporting
Expenses	1,588
Income (loss) from operations	(1,588)
Equity in earnings (losses) of unconsolidated ventures	3,215
Net income (loss)	1,627
Total Assets	123,538
Corporate
Segment Reporting
Expenses	3,758	797
Income (loss) from operations	(3,758)	(797)
Net income (loss)	(3,758)	(797)
Total Assets	$ 145,459		$ 212,521