Summary of Significant Accounting Policies (Details Textual) (USD $) In Thousands, unless otherwise specified	1 Months Ended		12 Months Ended
	Sep. 30, 2009	Sep. 30, 2008	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2005
Additional Summary of Significant Accounting Policies (Textual) [Abstract]
Above below market lease amortization			$ 1,431	$ 2,857	$ 4,273
Cash and liquid investment initial maturity			Three months or less
Accumulated amortization deferred financing cost			13,086	16,565
Allowance For Doubtful Accounts Receivable			2,675	3,001
Deferred rent receivable allowance amount			2,302	1,855
Minimum percentage of taxable income to be distributed			90.00%
Refunds from Internal Revenue Services (IRS)	40,418	3,767			40,418
Franchise tax reserve			(745)			745
In-Place Lease and Customer Relationship [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Amortization expense			$ 11,076	$ 14,185	$ 16,162