Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Scheduled future amortization of intangible assets [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 223,380	$ 228,768
Deferred Financing Costs [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1, 2015 through December 31, 2015	1,643
2016	3,035
2017	2,720
2018	1,538
2019	1,130
Thereafter	1,349
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 11,415	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 4 months
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1, 2015 through December 31, 2015	$ 20,519
2016	35,511
2017	30,630
2018	26,145
2019	21,716
Thereafter	53,743
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 188,264
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
Lease Incentives [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1, 2015 through December 31, 2015	$ 706
2016	1,238
2017	1,121
2018	1,015
2019	822
Thereafter	2,582
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 7,484
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]
July 1, 2015 through December 31, 2015	$ 2,213
2016	3,294
2017	2,294
2018	1,474
2019	1,054
Thereafter	2,870
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 13,199
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 1 month 5 days
Acquired finite-lived intangible assets, weighted average useful life (in years)	2 years 1 month 5 days
Acquisition-Related Intangible Assets (amortized in Depreciation and Amortization) [Member]
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Acquired finite-lived intangible assets, weighted average useful life (in years)	2 years 4 months
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1, 2015 through December 31, 2015	$ 273
2016	553
2017	553
2018	553
2019	553
Thereafter	533
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 3,018
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 6 months
Acquisition-Related Below Market Lease Liabilities [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
July 1, 2015 through December 31, 2015	$ (3,098)
2016	(5,555)
2017	(5,284)
2018	(5,123)
2019	(4,810)
Thereafter	(14,996)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (38,866)	$ (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)	7 years 9 months 20 days
Assumed finite-lived below market lease liabilities, weighted average useful life (in years)	4 years 9 months 20 days