Related Party Arrangements (Details) (USD $)	3 Months Ended	12 Months Ended		3 Months Ended				3 Months Ended			3 Months Ended			3 Months Ended			3 Months Ended					3 Months Ended			50 Months Ended		3 Months Ended					50 Months Ended	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 CRE debt investments	Mar. 31, 2013 PE Fund JV	Mar. 31, 2013 Organization costs	Mar. 31, 2012 Organization costs	Dec. 31, 2012 Organization costs	Mar. 31, 2013 Offering costs	Mar. 31, 2012 Offering costs	Dec. 31, 2012 Offering costs	Mar. 31, 2013 Operating costs	Mar. 31, 2012 Operating costs	Dec. 31, 2012 Operating costs	Mar. 31, 2013 Asset management fees	Mar. 31, 2012 Asset management fees	Dec. 31, 2012 Asset management fees	Mar. 31, 2013 Acquisition fees	Mar. 31, 2012 Acquisition fees	Mar. 31, 2013 Selling commissions / Dealer manager fees	Mar. 31, 2012 Selling commissions / Dealer manager fees	Dec. 31, 2012 Disposition fees	Mar. 31, 2013 Maximum	Mar. 31, 2013 Advisor quarter	Mar. 31, 2013 Advisor Operating costs	Mar. 31, 2013 Advisor Acquisition fees	Mar. 31, 2013 Advisor Disposition fees	Mar. 31, 2013 Advisor Maximum	Mar. 31, 2013 Dealer Manager	Mar. 31, 2013 Dealer Manager Maximum	Mar. 31, 2013 Sponsor	Mar. 31, 2012 Sponsor	Mar. 31, 2013 Sponsor	Mar. 31, 2013 Sponsor PE Fund JV	Dec. 31, 2012 Sponsor PE Fund JV	Mar. 31, 2013 Sponsor Maximum
Organization and Offering Costs
Percentage of gross offering proceeds from the Primary Offering reimbursable as organization and offering costs																						15.00%					15.00%
Expected reimbursable organization and offering costs, excluding selling commissions and dealer manager fee																						$ 15,000,000					$ 15,000,000
Expected reimbursable organization and offering costs, excluding selling commissions and dealer manager fee, as a percentage of total proceeds available to be raised from the primary offering	1.50%																										1.50%
Gross proceeds from sale of shares	155,581,000	385,098,000																													1,100,000	4,600,000
Reimbursement of personnel costs related to executive officers and other personnel involved in activities for which the Advisor receives an acquisition fee, asset management fee or disposition fee																							0
Operating Costs
Number of preceding fiscal quarters at the end of which the Company reimburses operating costs (including the asset management fee)																							4
Period for true-up calculation of expense reimbursements																							12 months
Operating costs recorded in accounts payable and accrued expenses																								7,000,000
Allocable operating costs																								5,500,000
Percentage of average invested assets reimbursable as operating costs																											2.00%
Percentage of net income, without reduction for any additions to reserves for depreciation, loan losses or other similar non-cash reserves and excluding any gain from the sale of the Company's assets, considered for reimbursement of operating costs																											25.00%
Asset Management Fee
Monthly asset management fees as percentage of principal amount of debt originated																							1.25%
Asset Acquisition Fee
Asset acquisition fee as percentage of principal amount funded to originate CRE debt or other real estate investments																							1.00%
Asset Disposition Fee
Asset disposition fee as percentage of contract sales price of CRE debt, CRE security or select CRE equity investment sold																							1.00%
Asset disposition fee as a percentage of the principal amount of the CRE debt investment prior to the specified transaction																							1.00%
Selling Commissions and Dealer Manager Fees
Selling commissions as a percentage of gross offering proceeds from primary offering																													7.00%
Dealer manager fee as a percentage of gross offering proceeds from primary offering																												3.00%
Selling commissions or dealer manager fees are paid for sales under DRP	0																											0
Value of shares of common stock committed to be purchased																																			10,000,000
Shares purchased during the period																															100,000	500,000
Purchase price of common stock (in dollars per share)																														$ 9.00
Amount of transaction with related parties					53,000	152,000		1,003,000	987,000		1,485,000	275,000		2,142,000	307,000		2,342,000	256,000	16,935,000	7,399,000
Due to related party	2,793,000	15,165,000			20,000		113,000	377,000		2,151,000	1,485,000		523,000	840,000		559,000	71,000				24,000													11,800,000
Asset management fees recorded in accounts payable and accrued expenses			1,000,000	1,300,000
Fees deferred by advisor																									500,000	300,000
PE Fund JV
Ownership percentage				29.50%																													70.50%
Aggregate Cash contribution to fund				400,100,000
Cash contribution to fund				118,000,000																													282,100,000
Aggregated amount deposited in connection with funding obligations																																		$ 40,000,000