RELATED PARTY TRANSACTIONS (Details) (USD $)			12 Months Ended						12 Months Ended			1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009 Klaff [Member]	Dec. 31, 2011 Lead Trustee [Member]	Dec. 31, 2010 Lead Trustee [Member]	Dec. 31, 2009 Lead Trustee [Member]	Dec. 31, 2011 Unconsolidated Affiliates [Member]	Dec. 31, 2010 Unconsolidated Affiliates [Member]	Dec. 31, 2011 Core Portfolio [Member] Brandywine Portfolio [Member]	Dec. 31, 2010 Core Portfolio [Member] Brandywine Portfolio [Member]	Dec. 31, 2009 Core Portfolio [Member] Brandywine Portfolio [Member]	Feb. 28, 2010 Restricted Stock [Member] Klaff [Member]	Dec. 31, 2005 Restricted Stock [Member] Klaff [Member]
Related Party Transaction [Line Items]
Units issued for interest in contractual rights (in shares)													250,000
Units issued for interest in contractual rights, converted (in shares)												250,000
Related party revenue			$ 400,000						$ 1,000,000	$ 800,000	$ 700,000
Receivable from related parties	1,375,000	2,409,000					1,375,000	2,409,000
Related party transaction expense				$ 100,000	$ 100,000	$ 100,000