Intangible Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009
Intangible assets and liabilities, net [Abstract]
Deferred financing and leasing costs, accumulated amortization	$ (63,156)	$ (59,360)
Deferred financing and leasing costs, net	128,585	85,001
Deferred Financing Costs [Member]
Intangible assets and liabilities, net [Abstract]
Deferred financing and leasing costs, gross	18,044	16,331
Deferred financing and leasing costs, accumulated amortization	(5,797)	(7,031)
Deferred financing and leasing costs, net	12,247	9,300
Amortization of intangible assets and liabilities
Amortization of intangible assets	3,312	3,385	2,760
Scheduled future amortization of intangible assets and liabilities
2012	3,386
2013	2,982
2014	2,682
2015	2,073
2016	704
Thereafter	420
Total future amortization of intangible assets and liabilities	12,247
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	3.7
Deferred Leasing Costs [Member]
Intangible assets and liabilities, net [Abstract]
Deferred financing and leasing costs, gross	173,697	128,030
Deferred financing and leasing costs, accumulated amortization	(57,359)	(52,329)
Deferred financing and leasing costs, net	116,338	75,701
Amortization of intangible assets and liabilities
Amortization of intangible assets	20,980	17,383	15,064
Scheduled future amortization of intangible assets and liabilities
2012	25,082
2013	20,503
2014	16,336
2015	12,411
2016	9,226
Thereafter	22,095
Total future amortization of intangible assets and liabilities	105,653
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	6.4
Deferred Lease Incentives [Member]
Amortization of intangible assets and liabilities
Amortization of intangible assets	1,371	1,239	1,110
Scheduled future amortization of intangible assets and liabilities
2012	1,291
2013	1,136
2014	973
2015	752
2016	579
Thereafter	2,186
Total future amortization of intangible assets and liabilities	6,917
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	8.0
Acquisition Related Intangible Assets [Member]
Amortization of intangible assets and liabilities
Amortization of intangible assets	915	531	102
Scheduled future amortization of intangible assets and liabilities
2012	1,054
2013	822
2014	527
2015	342
2016	281
Thereafter	742
Total future amortization of intangible assets and liabilities	3,768
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	5.8
Acquisition-Related Intangible Liabilities [Member]
Intangible assets and liabilities, net [Abstract]
Acquisition-related intangible liabilities, gross	16,441	733
Acquisiton-related intangible liabilities, accumulated amortization	(971)	(200)
Acquisition-related intangible liabilities, net	15,470	533
Amortization of intangible assets and liabilities
Amortization of acquisition-related intangible liabilities	(840)	(96)	(94)
Scheduled future amortization of intangible assets and liabilities
2012	(2,123)
2013	(2,094)
2014	(2,019)
2015	(1,808)
2016	(1,511)
Thereafter	(5,915)
Total future amortization of intangible assets and liabilities	$ (15,470)
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Finite-lived intangible liabilities, average useful life (in years)	8.6