Related Party Arrangements (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	6 Months Ended	12 Months Ended	53 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended					3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		53 Months Ended	3 Months Ended	6 Months Ended	53 Months Ended		3 Months Ended		6 Months Ended							3 Months Ended	6 Months Ended		53 Months Ended	6 Months Ended
	Jun. 30, 2013 investment	Dec. 31, 2012 investment	Jun. 30, 2013	Jun. 30, 2013 PE Investment I	Jun. 30, 2013 PE Investment II	Jun. 30, 2013 PE Investment II	Jun. 30, 2013 Advisor	Dec. 31, 2012 Advisor	Jun. 30, 2013 Advisor PE Investment I	Dec. 31, 2012 Advisor PE Investment I	Jun. 30, 2013 Advisor Organization costs	Jun. 30, 2012 Advisor Organization costs	Jun. 30, 2013 Advisor Organization costs	Jun. 30, 2012 Advisor Organization costs	Dec. 31, 2012 Advisor Organization costs	Jun. 30, 2013 Advisor Offering costs	Jun. 30, 2012 Advisor Offering costs	Jun. 30, 2013 Advisor Offering costs	Jun. 30, 2012 Advisor Offering costs	Dec. 31, 2012 Advisor Offering costs	Jun. 30, 2013 Advisor Operating costs	Jun. 30, 2012 Advisor Operating costs	Jun. 30, 2013 Advisor Operating costs Q	Jun. 30, 2012 Advisor Operating costs	Dec. 31, 2012 Advisor Operating costs	Jun. 30, 2013 Advisor Asset management fees	Jun. 30, 2012 Advisor Asset management fees	Jun. 30, 2013 Advisor Asset management fees	Jun. 30, 2012 Advisor Asset management fees	Dec. 31, 2012 Advisor Asset management fees	Jun. 30, 2013 Advisor Acquisition fees	Jun. 30, 2012 Advisor Acquisition fees	Jun. 30, 2013 Advisor Acquisition fees	Jun. 30, 2012 Advisor Acquisition fees	Jun. 30, 2013 Advisor Acquisition fees	Jun. 30, 2013 Advisor Disposition fees	Jun. 30, 2013 Advisor Disposition fees	Jun. 30, 2013 Advisor Disposition fees	Dec. 31, 2012 Advisor Disposition fees	Jun. 30, 2013 Advisor Selling commissions / Dealer manager fees	Jun. 30, 2012 Advisor Selling commissions / Dealer manager fees	Jun. 30, 2013 Advisor Selling commissions / Dealer manager fees	Jun. 30, 2012 Advisor Selling commissions / Dealer manager fees	Jun. 30, 2013 Advisor Maximum	Jun. 30, 2013 Advisor Maximum Operating costs	Jun. 30, 2013 Advisor Maximum Disposition fees	Jun. 30, 2013 Dealer Manager Selling commissions / Dealer manager fees	Jun. 30, 2013 Dealer Manager Maximum Selling commissions / Dealer manager fees	Jun. 30, 2012 Sponsor	Jun. 30, 2013 Sponsor	Jun. 30, 2012 Sponsor	Jun. 30, 2013 Sponsor	Jun. 30, 2013 Sponsor PE Investment I	Feb. 28, 2013 Sponsor PE Investment I	Dec. 31, 2012 Sponsor PE Investment I	Dec. 31, 2012 Sponsor PE Fund JV	Jun. 30, 2013 Sponsor Maximum
Organization and Offering Costs
Percentage of gross offering proceeds from the Primary Offering reimbursable as organization and offering costs																																												15.00%
Expected reimbursable organization and offering costs, excluding selling commissions and dealer manager fee																																												$ 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%
Gross proceeds from issuance of common stock	512,800,000	433,000,000	1,072,900,000				1,072,900,000
Estimated reimbursable organization and offering costs, excluding selling commissions and dealer manager fee							10,500,000
Estimated 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							1.00%
Gross proceeds from sale of shares	460,769,000	385,098,000																																															900,000		1,900,000	4,600,000
Maximum underwriting compensation including selling commissions, the dealer manager fee and amounts reimbursed							10.00%
Operating Costs
Number of preceding fiscal quarters at the end of which the Company reimburses operating costs (including the asset management fee)																							4
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%
Period for true-up calculation of expense reimbursements																							12 months
Allocable operating costs																					5,200,000		5,200,000
Reimbursement of personnel costs related to executive officers and other personnel involved in activities for which the Advisor receives an acquisition fee or disposition fee																							0
Asset Management Fee
Monthly asset management fees as percentage of principal amount of debt originated																												0.10417%
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
Purchase price of common stock (in dollars per share)																																																		$ 9.00
Shares purchased during the period																																																	0.1		0.2	0.5
Amount of transaction with related parties											9,000	118,000	62,000	270,000		1,502,000	768,000	2,505,000	1,755,000		2,218,000	763,000	3,754,000	1,098,000		2,761,000	511,000	4,903,000	818,000		2,981,000	2,321,000	5,323,000	2,577,000		15,000	15,000			32,577,000	8,678,000	49,511,000	16,078,000
Due to related party	3,636,000	15,165,000	3,636,000				5,657,000	3,370,000							113,000	1,124,000		1,124,000		2,151,000	2,148,000		2,148,000		523,000	981,000		981,000		559,000	1,404,000		1,404,000		1,404,000				24,000																	11,800,000
Fees deferred by advisor																																			500,000			300,000
Amount of payable due to related party									(2,000,000)	11,800,000
Number of CRE debt investments contributed	29	20
Principal amount of investments	945,910,000	543,619,000	945,910,000
PE Investments
Ownership percentage																																																						70.50%
Aggregate Cash contribution to fund				400,100,000
Cash contribution to fund	134,664,000			118,000,000																																																	282,100,000
Aggregated amount deposited in connection with funding obligations																																																							40,000,000
Amount deposited in connection with subscription agreement					50,000,000	50,000,000
Portion of amount deposited by the entity						$ 7,500,000