Rental Property - Deferred Leasing Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Above market lease, gross	$ 580,293		$ 580,293		$ 531,989
Deferred leasing intangibles assets, accumulated amortization	(257,790)		(257,790)		(237,456)
Above market lease, net	322,503		322,503		294,533
Below market lease, gross	34,175		34,175		30,791
Below market lease, accumulated amortization	(12,278)		(12,278)		(10,450)
Below market lease, net	21,897		21,897		20,341
Net decrease to rental revenue related to above and below market lease amortization	1,259	$ 1,521	2,555	$ 3,187
Below Market Lease, Net, Amortization Income, Fiscal Year Maturity [Abstract]
2017	2,583		2,583
2017	4,211		4,211
2018	3,506		3,506
2019	3,104		3,104
2020	1,854		1,854
Above market leases
Finite-Lived Intangible Assets [Line Items]
Above market lease, gross	78,476		78,476		70,668
Deferred leasing intangibles assets, accumulated amortization	(34,009)		(34,009)		(32,868)
Above market lease, net	44,467		44,467		37,800
Other intangible lease assets
Finite-Lived Intangible Assets [Line Items]
Above market lease, gross	501,817		501,817		461,321
Deferred leasing intangibles assets, accumulated amortization	(223,781)		(223,781)		(204,588)
Above market lease, net	278,036		278,036		$ 256,733
Amortization expense related to other intangible lease assets	17,420	$ 16,346	35,813	$ 32,259
Estimated Net Amortization of In-Place Leases, Leasing Commissions and Tenant Relationships
2017	34,702		34,702
2017	58,161		58,161
2018	45,676		45,676
2019	35,970		35,970
2020	$ 26,620		$ 26,620