Mortgage Loans On Real Estate (Details 1) (USD $)	1 Months Ended	12 Months Ended
	Oct. 02, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Mortgage Loans
Balance at January 1		$ 114,333,000	$ 110,395,000	$ 26,101,000
Purchase and advances	21,000,000	177,550,000	67,619,000	122,301,000
Proceeds from sale		(25,735,000)		(12,876,000)
Interest (received) accrued, net		516,000	(37,000)	361,000
Repayments		(45,089,000)	(70,289,000)	(15,064,000)
Loan accretion		8,333,000	13,401,000	8,782,000
Discount accretion received in cash		(15,720,000)	(13,290,000)
Reclass to investment in real estate				(19,210,000)
Reclass from loan securities			662,000
Reclass from equity investments			12,544,000
Conversion of 180 North Michigan loan to equity investments		(2,938,000)	(4,650,000)
Transfer 450W 14th St bridge loan to preferred equity investments			(2,022,000)
Balance at December 31		$ 211,250,000	$ 114,333,000	$ 110,395,000