Goodwill and Other Intangibles - Intangible Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Intangible lease liabilities:
Accumulated Amortization	$ 56,891	$ 38,340
Weighted-Average Useful Life	18 years 18 days
Intangible Lease Liabilities, Net	$ 224,023	251,692
Total Intangible Lease Assets [Member]
Intangible lease assets:
Accumulated amortization	565,600
Intangible Lease Assets, Net	1,478,884	1,771,532
In-Place Leases [Member]
Intangible lease assets:
Accumulated amortization	$ 494,131	398,770
Weighted-Average Useful Life	14 years 9 months 18 days
Intangible Lease Assets, Net	$ 1,192,756	1,458,354
Leasing Commissions [Member]
Intangible lease assets:
Accumulated amortization	$ 1,836	1,035
Weighted-Average Useful Life	9 years 10 months 24 days
Intangible Lease Assets, Net	$ 10,231	4,872
Above-Market Lease Assets and Deferred Lease Incentives [Member]
Intangible lease assets:
Accumulated amortization	$ 69,670	47,041
Weighted-Average Useful Life	16 years 5 months 23 days
Intangible Lease Assets, Net	$ 275,897	$ 308,306