ORGANIZATION (Details) $ in Thousands						1 Months Ended	12 Months Ended			85 Months Ended
	Mar. 08, 2016 USD ($)	Mar. 08, 2016 ILS (₪)	Mar. 07, 2016 ILS (₪)	Mar. 02, 2016 ILS (₪)	Mar. 01, 2016 ILS (₪)	Mar. 31, 2016	Dec. 31, 2016 USD ($) a portfolio property investment shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2016 USD ($) a portfolio property investment shares	Dec. 18, 2015 certificate shares	Oct. 23, 2012 USD ($) shares	Dec. 29, 2011 USD ($) shares	Jan. 08, 2009 shares
Organizational Structure [Line Items]
Common stock, shares authorized (in shares)							1,000,000,000	1,000,000,000		1,000,000,000
Common stock, shares issued (in shares)							56,775,767	58,696,115		56,775,767		55,249	220,994
Partnership interest in Operating Partnership							0.10%
Partnership interest in the Operating Partnership and is its sole limited partner							99.90%
Issuance of common stock, value | $							$ 12,616	$ 13,573	$ 9,911
Shares of common stock sold under dividend reinvestment plan, value | $										$ 65,400
Redemptions of common stock, value | $							38,573	30,100	$ 5,104	77,000
Common stock, value, issued | $							$ 568	$ 587		$ 568		$ 500	$ 2,000
Number of investments in unconsolidated joint venture | investment							2			2
Number of investments in debt securities | investment							1			1
Office Properties [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							11			11
Office Campus [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							1			1
Office Buildings, Campus [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							9			9
Office Portfolio [Member]
Organizational Structure [Line Items]
Number of real estate properties | portfolio							1			1
Office Buildings, Portfolio [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							4			4
Undeveloped Land, Portfolio [Member]
Organizational Structure [Line Items]
Real estate area of undeveloped land | a							25			25
Office/Flex/Industrial Portfolio [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							1			1
Office/Flex/Industrial Buildings [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							21			21
Office Properties, Portfolio [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							3			3
Retail Property, Portfolio [Member]
Organizational Structure [Line Items]
Number of real estate properties | property							1			1
Apartment Properties, Portfolio [Member]
Organizational Structure [Line Items]
Number of real estate properties acquired through foreclosure | property							2			2
Undeveloped Land [Member]
Organizational Structure [Line Items]
Real estate area of undeveloped land | a							1,670			1,670
Number of investments in real estate | investment							2			2
Series A Debentures [Member] | Bonds Payable [Member]
Organizational Structure [Line Items]
Maximum borrowing capacity | ₪				₪ 1,000,000,000
Interest rate during period						4.25%
Proceeds from issuance of debt	$ 249,200	₪ 970,200,000	₪ 127,700,000		₪ 842,500,000
Principal installment payments required as percent of total debt				20.00%
Maximum [Member] | Series A Debentures [Member] | Bonds Payable [Member]
Organizational Structure [Line Items]
Interest rate during period				4.25%
Common Stock [Member]
Organizational Structure [Line Items]
Shares registered in primary offering (in shares)														100,000,000
Shares registered for sale under dividend reinvestment plan (in shares)														40,000,000
Issuance of common stock, shares							938,662	1,114,532	901,146	56,584,976
Issuance of common stock, value | $							$ 9	$ 11	$ 9	$ 561,700
Shares of common stock sold under dividend reinvestment plan, shares										6,035,169.882
Redemptions of common stock, shares							2,859,010	2,462,746	475,817	6,140,621.9524
Redemptions of common stock, value | $							$ 28	$ 24	$ 5
Common Stock [Member] | Minimum [Member]
Organizational Structure [Line Items]
Stock offering, shares authorized for issuance (in shares)														250,000
Common Stock [Member] | Maximum [Member]
Organizational Structure [Line Items]
Stock offering, shares authorized for issuance (in shares)														140,000,000
KBS Capital Advisors LLC [Member]
Organizational Structure [Line Items]
Shares held by affiliate (in shares)							20,000			20,000
KBS Strategic Opportunity BVI [Member]
Organizational Structure [Line Items]
Common stock, shares authorized (in shares)											50,000
Number of certificates issued | certificate											1
KBS Strategic Opportunity BVI [Member] | Operating Partnership [Member]
Organizational Structure [Line Items]
Common stock, shares issued (in shares)											10,000