ORGANIZATION (Details) (USD $)	6 Months Ended	12 Months Ended	15 Months Ended	6 Months Ended	12 Months Ended	15 Months Ended
	Jun. 30, 2012 MortgageLoans	Dec. 31, 2011	Jun. 30, 2012 MortgageLoans	Jun. 30, 2012 Common Stock [Member]	Dec. 31, 2011 Common Stock [Member]	Jun. 30, 2012 Common Stock [Member]	Feb. 04, 2010 Common Stock [Member]	Jun. 30, 2012 Office Properties [Member] properties	Feb. 04, 2010 Minimum [Member] Common Stock [Member]	Feb. 04, 2010 Maximum [Member] Common Stock [Member]	Jan. 26, 2010 KBS Capital Advisors LLC [Member]	Aug. 07, 2009 KBS Capital Advisors LLC [Member]
Organizational Structure [Line Items]
Partnership interest in Operating Partnership	0.10%
Partnership interest in the Operating Partnership and is its sole limited partner	99.90%
Common stock, shares issued	19,642,038	10,468,043	19,642,038									20,000
Common stock, purchase price per share											$ 10.00
Shares held by affiliate				20,000		20,000
Number of real estate properties								5
Number of first mortgage loan secured by a deed of trust	1		1
Stock offering, shares authorized for issuance									250,000	280,000,000
Shares of common stock authorized under dividend reinvestment plan, shares							80,000,000
Issuance of common stock, shares				9,224,538	10,448,043	19,672,581
Issuance of common stock, value	$ 91,924,000	$ 104,030,000	$ 196,000,000	$ 92,000	$ 104,000
Shares of common stock sold under dividend reinvestment plan, shares						285,989
Shares of common stock sold under dividend reinvestment plan, value			2,700,000
Redemptions of common stock, shares				50,543		50,543
Redemptions of common stock, value	$ 503,000		$ 500,000	$ 1,000