Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Scheduled future amortization of intangible assets [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 227,826	$ 227,826	$ 166,009
Deferred Financing Costs [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1, 2013 through December 31, 2013	865	865
2014	3,233	3,233
2015	2,599	2,599
2016	1,500	1,500
2017	1,213	1,213
Thereafter	1,464	1,464
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	10,874	10,874	13,897
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)		5 years 1 month 15 days
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1, 2013 through December 31, 2013	10,222	10,222
2014	38,795	38,795
2015	32,028	32,028
2016	26,229	26,229
2017	22,312	22,312
Thereafter	57,402	57,402
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	186,988	186,988
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)		6 years 8 months 12 days
Lease Incentives [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1, 2013 through December 31, 2013	320	320
2014	1,199	1,199
2015	971	971
2016	794	794
2017	729	729
Thereafter	2,553	2,553
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	6,566	6,566
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)		7 years 11 months
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1, 2013 through December 31, 2013	1,240	1,240
2014	4,401	4,401
2015	3,627	3,627
2016	2,815	2,815
2017	2,265	2,265
Thereafter	5,058	5,058
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	19,406	19,406
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)		6 years 8 months 12 days
Acquired finite-lived intangible assets, average useful life (in years)	6 years 6 months
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1, 2013 through December 31, 2013	138	138
2014	553	553
2015	553	553
2016	553	553
2017	553	553
Thereafter	1,642	1,642
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	3,992	3,992
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)		7 years 2 months 13 days
Acquisition-Related Below Market Lease Liabilities [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
October 1, 2013 through December 31, 2013	(1,567)	(1,567)
2014	(6,011)	(6,011)
2015	(5,728)	(5,728)
2016	(5,414)	(5,414)
2017	(5,165)	(5,165)
Thereafter	(24,538)	(24,538)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (48,423)	$ (48,423)	$ (33,636)
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived below market lease liabilities, average useful life (in years)		9 years 4 months
Assumed finite-lived below market lease liabilities, average useful life (in years)	8 years 11 months
in-Place Lease Intangible Assets [Member]
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Acquired finite-lived intangible assets, average useful life (in years)	6 years 6 months