Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ 53,483	$ 103,458
Goodwill	1,674	3,647	$ 3,867
Total intangible assets	245,529	124,615
In-place leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	185,251	112,937
Accumulated amortization	46,899	88,035
Above Market Rents
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	40,260	8,031
Accumulated amortization	6,515	15,423
Below-market ground leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	18,344	$ 0
Accumulated amortization	$ 69