Other Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Other Assets
Total other assets	$ 81,806	$ 76,285
Leasing commissions, net of accumulated amortization [Member]
Other Assets
Total other assets	19,906	18,207
Acquired above market leases, net [Member]
Other Assets
Total other assets	12,796	16,771
Acquired in-place leases, net [Member]
Other Assets
Total other assets	36,047	28,888
Lease incentives, net of accumulated amortization [Member]
Other Assets
Total other assets	1,573	1,850
Other intangible assets, net of accumulated amortization [Member]
Other Assets
Total other assets	973	987
Debt issuance costs, net of accumulated amortization [Member]
Other Assets
Total other assets	3,561	3,392
Purchase deposit [Member]
Other Assets
Total other assets	2,000	3,000
Prepaid expenses, deposits, and other [Member]
Other Assets
Total other assets	$ 4,950	$ 3,190