Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Scheduled future amortization of intangible assets [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 218,976	$ 231,765
Scheduled future amortization of below market lease liabilities [Abstract]
Total scheduled future amortization of acquisition-related below market lease liabilities	(40,037)	$ (45,903)
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1 through December 31, 2016	11,797
2017	41,426
2018	34,194
2019	28,606
2020	23,983
Thereafter	58,905
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 198,911
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 through December 31, 2016	$ 358
2017	1,399
2018	1,294
2019	1,080
2020	805
Thereafter	2,544
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 7,480
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 4 months 24 days
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1 through December 31, 2016	$ 917
2017	2,657
2018	1,713
2019	1,322
2020	1,002
Thereafter	2,653
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 10,264
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
Acquired finite-lived intangible assets, average useful life (in years)	9 years 9 months 18 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, average useful life (in years)	10 years 2 months 12 days
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1 through December 31, 2016	$ 137
2017	553
2018	553
2019	553
2020	525
Thereafter	0
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 2,321
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
Acquisition-Related Below Market Lease Liabilities [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
October 1 through December 31, 2016	$ (1,737)
2017	(6,231)
2018	(6,022)
2019	(5,549)
2020	(5,223)
Thereafter	(15,275)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (40,037)
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 6 months
Assumed finite-lived below market lease liabilities, average useful life (in years)	11 years 2 months 12 days