Business and Organization (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended	12 Months Ended	53 Months Ended			53 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013	Jul. 03, 2013	Jul. 02, 2013	Jul. 02, 2013 Subsequent event	Jul. 03, 2013 Subsequent event	Jun. 30, 2013 Maximum
Authorized shares of common stock and preferred stock
Common stock, shares authorized	400,000,000	400,000,000	400,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000	50,000,000					50,000,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock filed in a registration statement with SEC, for issuance pursuant to primary offering (in shares)								100,000,000
Common stock filed in a registration statement with SEC, for issuance pursuant to DRP (in shares)				15,000,000	7,600,000	15,000,000		10,526,315
Additional shares authorized for issuance pursuant to the dividend reinvestment plan (DRP)							15,000,000
Gross proceeds from Total Primary Offering	$ 512.8	$ 433.0	$ 1,072.9
Gross proceeds from Total Offering						$ 1,128.4