Reportable Segments - Summary of Assets by Business Segment (Detail) (USD $) In Thousands, unless otherwise specified					9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2013 Operating Segments [Member]	Dec. 31, 2012 Operating Segments [Member]
Assets
Operating properties					$ 630,666	$ 562,822
Loan assets					154,265	239,534
REIT securities	7,074	19,694			7,074	19,694
Cash and cash equivalents	165,762	97,682	159,251	40,952	165,762	97,682
Restricted cash	19,084	13,250			7,387
Accounts receivable and prepaids					574	336
Deferred financing costs					2,757	3,095
TOTAL ASSETS	968,485	923,163			968,485	923,163
Capital Expenditures
Operating Properties					$ 2,835	$ 12,417