Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Scheduled future amortization of intangible assets [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	$ 228,768	$ 222,211
Deferred Financing Costs [Member]
Scheduled future amortization of intangible assets [Abstract]
2015	3,064
2016	2,794
2017	2,517
2018	1,387
2019	660
Thereafter	1,103
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	11,525	12,159
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Intangible assets, weighted average useful life (in years)	4 years 4 months 25 days
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Scheduled future amortization of intangible assets [Abstract]
2015	40,621
2016	34,317
2017	30,109
2018	25,650
2019	21,285
Thereafter	39,960
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	191,942
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Intangible assets, weighted average useful life (in years)	6 years 6 months
Lease Incentives [Member]
Scheduled future amortization of intangible assets [Abstract]
2015	1,214
2016	1,051
2017	978
2018	874
2019	686
Thereafter	2,148
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	6,951
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Intangible assets, weighted average useful life (in years)	8 years
Acquisition-Related Intangible Assets (in Rental and Other Revenue) [Member]
Scheduled future amortization of intangible assets [Abstract]
2015	4,375
2016	3,057
2017	2,255
2018	1,463
2019	1,047
Thereafter	2,859
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	15,056
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Intangible assets, weighted average useful life (in years)	6 years 2 months 12 days
Acquired intangible assets, weighted average useful life (in years)	3 years 4 months 25 days
Acquisition-Related Intangible Assets (amortized in Depreciation and Amortization) [Member]
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Acquired intangible assets, weighted average useful life (in years)	5 years 4 months 25 days
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Scheduled future amortization of intangible assets [Abstract]
2015	553
2016	553
2017	553
2018	553
2019	553
Thereafter	529
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	3,294
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Intangible assets, weighted average useful life (in years)	6 years
Acquisition-Related Below Market Lease Liabilities [Member]
Scheduled future amortization of below market lease liabilites [Abstract]
2015	(5,990)
2016	(5,673)
2017	(5,410)
2018	(5,247)
2019	(4,915)
Thereafter	(15,000)
Total scheduled future amortization of below market lease liabilities	$ (42,235)	$ (46,845)
Weighted average remaining amortization periods for intangible assets and liabilities [Abstract]
Below market lease liabilities, weighted average useful life (in years)	8 years 2 months 12 days
Assumed finite-lived below market lease liabilities, weighted average useful life (in years)	5 years 6 months