Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Scheduled future amortization of intangible assets [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 224,270	$ 228,768
Deferred Financing Costs [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1, 2015 through December 31, 2015	2,299
2016	2,784
2017	2,508
2018	1,379
2019	653
Thereafter	1,124
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	10,747	11,525
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	4 years 2 months 12 days
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1, 2015 through December 31, 2015	30,616
2016	34,322
2017	29,907
2018	25,334
2019	21,021
Thereafter	48,503
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	189,703
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 10 months 25 days
Lease Incentives [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1, 2015 through December 31, 2015	887
2016	1,072
2017	1,000
2018	893
2019	705
Thereafter	2,214
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	6,771
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	8 years
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1, 2015 through December 31, 2015	3,216
2016	3,054
2017	2,253
2018	1,462
2019	1,046
Thereafter	2,858
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	13,889
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 2 months 12 days
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1, 2015 through December 31, 2015	415
2016	553
2017	553
2018	553
2019	553
Thereafter	533
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	3,160
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 8 months 12 days
Acquisition-Related Below Market Lease Liabilities [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
April 1, 2015 through December 31, 2015	(4,700)
2016	(5,570)
2017	(5,298)
2018	(5,135)
2019	(4,804)
Thereafter	(14,996)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (40,503)	$ (42,235)
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)	8 years