Equity Investments (Details Textual) (USD $)	9 Months Ended			9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	May 02, 2012	Sep. 30, 2012 Marc Realty [Member]	Sep. 30, 2012 Socal Office Portfolio Loan [Member]	Sep. 30, 2012 Socal Office Portfolio Loan [Member]	Sep. 28, 2012 Socal Office Portfolio Loan [Member]	Dec. 31, 2011 Socal Office Portfolio Loan [Member]	Sep. 18, 2012 ROIC - Riverside LLC [Member]
Equity Investment [Line Items]
Return on capital contribution							$ 44,224,000		$ 15,600,000
Allocable share of distribution							38,407,000		7,800,000
Transfer from loans receivable	2,938,000	6,534,000		2,938,000
Transfer from preferred equity	3,923,000	2,022,000		3,923,000
Transfer to equity investment	6,861,000	4,650,000		6,861,000
Total assets					136,000	136,000		97,989,000
Total liabilities					116,000	116,000		269,000
Net Income					17,999,000	16,900,000
Proceeds from repurchase agreement									38,100,000
Equity Investments (Textual) [Abstract]
Aggregate price of acquisition of its interest			$ 7,000,000
Percentage of interest in Concord Debt Holdings LLC			33.33%