Other Assets (Composition of Other Assets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Lease intangible assets, net	$ 130,623	$ 92,559
Leasing commissions, net	32,537	28,643
Prepaid expenses and other receivables	25,641	2,178
Straight-line rent receivable, net	20,340	17,266
Deposits and mortgage escrow	14,248	34,567
Deferred financing costs, net	9,487	8,663
Deferred tax asset	2,985	3,229
Furniture and fixtures, net	2,389	2,234
Total other assets	238,250	189,339
Environmental Remediation Asset [Member]
Prepaid expenses and other receivables	$ 20,000