Business Segments (Details 2) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Other financial information
Revenues	$ 40,420	$ 28,905	$ 73,542	$ 58,301
Interest income	9	9	20	17
Interest expense	3,578	1,735	5,986	3,388
Investment in non-consolidated REITs	88,654	90,782	88,654	90,782	89,327
Capital expenditures	4,091	1,433	7,046	3,118
Identifiable assets	1,303,764	1,186,901	1,303,764	1,186,901	1,238,735
Real Estate Operations
Other financial information
Revenues	34,762	27,612	66,676	56,741
Interest income	5	9	15	17
Interest expense	3,578	1,735	5,986	3,388
Investment in non-consolidated REITs	88,654	90,782	88,654	90,782
Capital expenditures	4,091	1,371	7,046	3,056
Identifiable assets	1,293,933	1,183,161	1,293,933	1,183,161
Investment Banking/Investment Services
Other financial information
Revenues	5,658	1,293	6,866	1,560
Interest income	4		5
Capital expenditures		62		62
Identifiable assets	$ 9,831	$ 3,740	$ 9,831	$ 3,740