Summary of Significant Accounting Policies - Revenues - Accounts Receivables (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 joint_venture	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Document Fiscal Year Focus	2013
Current Fiscal Year End Date	--12-31
Number of Joint Ventures, Unilateral Dissolution Right	5
Provision for doubtful accounts	$ 1,841	$ 3,006	$ 3,166
Other receivables	7,411	8,582
Less: allowance for doubtful accounts	(3,922)	(3,915)
Accounts Receivable, Net	26,319	26,601
Percentage Of Revenue By Customer	5.00%
CAM and Tax Reimbursements
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	16,280	17,891
Tenant Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	6,550	4,043
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage Of Revenue By Customer	5.00%
Discontinued operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for doubtful accounts	$ 53	$ 58	$ 354