Reportable Segments - Summary of Assets by Business Segment (Detail) (USD $) In Thousands, unless otherwise specified					6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2013 Operating Segments [Member]	Dec. 31, 2012 Operating Segments [Member]
Summary of assets by business segment
Operating properties					$ 603,822	$ 562,822
Loan assets					143,655	239,534
REIT securities					10,360	19,694
Cash and cash equivalents	186,132	97,682	43,959	40,952	186,132	97,682
Restricted cash	19,422	13,250			2,802
Accounts receivable and prepaids					670	336
Deferred financing costs					2,869	3,095
TOTAL ASSETS	950,310	923,163			950,310	923,163
Capital Expenditures
Operating Properties					$ 2,552	$ 12,417