Organization - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended
	Dec. 31, 2012	Mar. 31, 2013 Segment
Organization [Line Items]
Percentage of REIT taxable income distributed to stockholders		90.00%
Number of reportable segments		1
Contribution of assets in exchange of common units	10,289,192
Percentage of interest owned by the parent company	25.00%
Unconsolidated joint venture [Member]
Organization [Line Items]
Investment portfolio		2.5
Investment portfolio percentage		2.00%
Wholly-owned and majority-owned real estate [Member]
Organization [Line Items]
Investment portfolio		147.1
Investment portfolio percentage		85.00%
Loan investment [Member]
Organization [Line Items]
Investment portfolio		22.6
Investment portfolio percentage		13.00%
Tiptree [Member]
Organization [Line Items]
Contribution of assets in exchange of common units	31,147,371
Percentage of interest owned by the parent company	75.00%
Tiptree [Member] | Class B Common Stock [Member]
Organization [Line Items]
Contribution of assets in exchange of common units	31,147,371