Goodwill and Other Intangibles (Intangible Lease Assets and Liabilities) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible lease liabilities, accumulated amortization	$ 33,493	$ 19,123
Below Market Lease, Weighted-Average Useful Life	17 years 5 months 9 days
Intangible lease liabilities, net	$ 264,232	317,838
Total Intangible Lease Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible lease assets, net	1,909,752	2,175,982
In-Place Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible lease assets, accumulated amortization	$ 361,315	236,096
Intangible lease assets, Weighted-Average Useful Life	14 years 22 days
Intangible lease assets, net	$ 1,575,024	1,816,508
Leasing Commissions [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible lease assets, accumulated amortization	$ 853	505
Intangible lease assets, Weighted-Average Useful Life	7 years 9 months 4 days
Intangible lease assets, net	$ 3,779	4,205
Above-Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible lease assets, accumulated amortization	$ 41,449	22,471
Intangible lease assets, Weighted-Average Useful Life	16 years 6 months
Intangible lease assets, net	$ 330,949	$ 355,269